While the free Adobe Reader lets you view PDFs, some advanced editing requires Adobe Acrobat. Examples include the following:
For more information, see this detailed comparison of Acrobat and Reader features.
If you receive a password-protected PDF, use the designated password to open the document. Some secured documents have restrictions that prevent you from printing, editing, or copying content. If a document has restricted features, any tools and menu items related to those features are dimmed in Reader.
If you have trouble opening a PDF, or if you are restricted from using certain features, contact the author of the PDF.
The free Adobe Reader cannot combine multiple PDF files; however, Adobe Acrobat can. For more information, see PDF Portfolios and combined PDFs in Acrobat Help.
PDF files are stored in a variety of folders on your computer, depending upon whether you received the PDF in email, from the web, or via another source.
To quickly find a PDF, search for the filename in Windows or Mac OS. Then navigate to the found folder, right-click the PDF file, and choose Delete (Windows) or Move to Trash (Mac OS).