You have lots of control and lots of possibilities for running effective and efficient searches in Adobe Acrobat DC. A search can be broad or narrow, including many different kinds of data and covering multiple Adobe PDFs.
If you work with large numbers of related PDFs, you can define them as a catalog in Acrobat Pro DC, which generates a PDF index for the PDFs. Searching the PDF index—instead of the PDFs themselves—dramatically speeds up searches. See Creating PDF indexes.
You run searches to find specific items in PDFs. You can run a simple search, looking for a search term within in a single file, or you can run a more complex search, looking for various kinds of data in one or more PDFs. You can selectively replace text.
You can run a search using either the Search window or the Find toolbar. In either case, Acrobat searches the PDF body text, layers, form fields, and digital signatures. You can also include bookmarks and comments in the search. Only the Find toolbar includes a Replace With option.
The Search window offers more options and more kinds of searches than the Find toolbar. When you use the Search window, object data and image XIF (extended image file format) metadata are also searched. For searches across multiple PDFs, Acrobat also looks at document properties and XMP metadata, and it searches indexed structure tags when searching a PDF index. If some of the PDFs you search have attached PDFs, you can include the attachments in the search.
PDFs can have multiple layers. If the search results include an occurrence on a hidden layer, selecting that occurrence displays an alert that asks if you want to make that layer visible.
Where you start your search depends on the type of search you want to run. Use the Find toolbar for a quick search of the current PDF and to replace text. Use the Search window to look for words or document properties across multiple PDFs, use advanced search options, and search PDF indexes.
A. Find field B. Find Previous C. Find Next D. Replace With expands to provide text field
Acrobat resizes and arranges the two windows side by side so that together they almost fill the entire screen.
Note: Clicking the Arrange Windows button a second time resizes the document window but leaves the Search window unchanged. If you want to make the Search window larger or smaller, drag the corner or edge, as you would to resize any window on your operating system.
The Find toolbar searches the currently open PDF. You can selectively replace the search term with alternative text. You replace text one instance at a time. You cannot make a global change throughout a PDF or across multiple PDFs.
Whole Words Only
Finds only occurrences of the complete word you type in the text box. For example, if you search for the word stick, the words tick and sticky aren’t found.
Finds only occurrences of the words that match the capitalization you type. For example, if you search for the word Web, the words web and WEB aren’t found.
The Search window enables you to look for search terms in multiple PDFs. For example, you can search across all PDFs in a specific location or all files in an open PDF Portfolio. The Replace With option is not availble in the Search window.
If documents are encrypted (have security applied to them), you cannot search them as part of a multiple-document search. Open those documents first and search them one at a time. However, documents encrypted as Adobe Digital Editions are an exception and can be searched as part of a multiple-document search.
During a search, you can click a result or use keyboard shortcuts to navigate the results without interrupting the search. Clicking the Stop button under the search-progress bar cancels further searching and limits the results to the occurrences already found. It doesn’t close the Search window or delete the Results list. To see more results, run a new search.
After you run a search from the Search window, the results appear in page order, nested under the names of each searched document. Each item listed includes a few words of context (if applicable) and an icon that indicates the type of occurrence.
The icon next to an instance of the search results indicates the search area in which the instance appears. Selecting an icon has the following effect:
Makes the document active in the document window. Expand the list to show the individual search results within that document.
(General) Search Result icon
In PDFs, jumps to that instance of the search term, usually in the body text of the PDF. The instance of the search term is highlighted in the document.
Non-PDF Search Result or Metadata icon 
In non-PDF files, opens the file; or if opening of that file type is restricted, opens a message dialog box.
May open a message indicating that the layer is hidden and asking if you want to make it visible.
Opens a file that is attached to the searched parent PDF and shows the highlighted instances of the search terms.
You can save the search results as a PDF or CSV file. For a video, see Saving Search Results in Acrobat.
By default, the Search window displays basic search options. Click Show More Options near the bottom of the window to display additional options. To restore the basic options, click Show Less Options near the bottom of the window.
You can set a preference so that More search options always appear in the Search window. In the Preferences dialog box under Categories, select Search.
Restricts the search to the current PDF, all of a currently open PDF Portfolio (if applicable), an index, or a location on your computer. If you choose to search an index, a location, or a PDF Portfolio, additional options appear under Use These Additional Criteria.
Uses the Boolean operators that you type with the search words into the What Word Or Phrase Would You Like To Search For box. Available only for searching multiple PDFs or PDF indexes.
Note: You cannot run wildcard searches using asterisks (*) or question marks (?) when searching PDF indexes.
Use These Additional Criteria (text options)
Includes the basic search options plus five additional options:
Finds words that contain part (the stem) of the specified search word. For example, a search for opening finds instances of open, opened, opens, and openly. This option applies to single words and phrases when you search the current PDF, a folder, or an index created with Acrobat 6.0 or later. Wildcard characters (*, ?) aren’t permitted in stemming searches. Stemming isn’t available if either Whole Words Only or Case-Sensitive is selected.
Use These Additional Criteria (document properties)
Appears only for searches across multiple PDFs or PDF indexes. You can select multiple property-modifier-value combinations and apply them to searches. This setting does not apply to non-PDF files inside PDF Portfolios.
Note: You can search by document properties alone by using document property options in combination with a search for specific text.
Applies the criteria set in the three connected options to the search. (The check box is selected automatically when you enter information in any of the three options for that set. After you enter options, deselecting the check box doesn’t clear the entries; they just aren’t applied to the search.)
Commonly used Boolean operators include the following:
Use between two words to find documents that contain both terms, in any order. For example, type paris AND france to identify documents that contain both paris and france. Searches with AND and no other Boolean operators produce the same results as selecting the All Of The Words option.
Use before a search term to exclude any documents that contain that term. For example, type NOT kentucky to find all documents that don’t contain the word kentucky. Or, type paris NOT kentucky to find all documents that contain the word paris but not the word kentucky.
Use to search for all instances of either term. For example, type email OR e-mail to find all documents with occurrences of either spelling. Searches with OR and no other Boolean operators produce the same results as selecting the Any Of The Words option.
^ (exclusive OR)
Use to search for all instances that have either term but not both. For example, type cat ^ dog to find all documents with occurrences of either cat or dog but not both cat and dog.
Use parentheses to specify the order of evaluation of terms. For example, type white AND (whale OR ahab) to find all documents that contain either white and whale or white and ahab. (The query processor performs an OR query on whale and ahab and then performs an AND query on those results with white.)
To learn more about Boolean queries, syntax, and other Boolean operators that you can use in your searches, refer to any standard text, website, or other resource with complete Boolean information.
A full-text index is created when someone uses Acrobat to define a catalog of PDFs. You can search that index rather than running a full-text search of each individual PDF in the catalog. An index search produces a results list with links to the occurrences of the indexed documents.
To search a PDF index, you must open Acrobat as a stand-alone application, not within your web browser.
In Mac OS, indexes created with some older versions of Acrobat are not compatible with the Acrobat X Search feature. If you have upgraded recently, update the index before using Acrobat X to search.
Ignore Asian Character Width
Finds both half-width and full-width instances of the Asian language characters in the search text.
Ignore Diacritics And Accents
Finds the search terms with any variation of the alphabetical characters. For example, typing cafe finds both cafe and café. Likewise, typing café finds both versions. If this option isn’t selected, typing cafe doesn’t find café, and vice versa.
Always Show More Options in Advanced Search
Shows the additional options available in the Search window, in addition to the basic options.
Show Document Title In Search Results
Displays document titles in search results. If a document does not have a title, displays the filename. When deselected, displays filenames in search results.
Maximum Number Of Documents Returned In Results
Limits the search results in the Search PDF window to a specific number of documents. The default value is 500, but you can enter any number from 1 to 10,000.
Range Of Words For Proximity Searches
Limits the search results to those in which the number of words between the search terms isn’t greater than the number you specify. Accepts a range from 1 to 10,000.
Enable Fast Find
Generates a cache of information from any PDF that you search. This cache reduces subsequent search times for that PDF.
Maximum Cache Size
Limits the temporary cache of search information for the Fast Find option to the specified size in megabytes (from 5 to 100,000). The default setting is 100.