While the free Adobe Acrobat Reader DC lets you view PDFs, some advanced editing requires Adobe Acrobat DC. Examples include the following:
Scanning to PDF
Creating new forms (Reader DC can fill out existing forms)
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 DC.
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 DC cannot combine multiple PDF files; however, Adobe Acrobat DC can. For more information, see Combine or merge files into single PDF in Acrobat Help.
PDF files are stored in various 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).