If you don't need the white borders around the content of a PDF, remove them in Adobe Acrobat XI by using the Crop tool. Don't worry -- you don't have to manually crop each page in a 200-page document; Acrobat offers a handy option to automatically remove white margins from all pages at once. If, however, your PDF contains scanned images, Acrobat will be unable to crop them because they don't contain the pixel-free margins of regular distilled PDFs that come from programs such as Microsoft Word or Adobe InDesign. If this is the case, manually crop the scans.
Removing Unnecessary Borders
Press "Ctrl-O," select the PDF you want to edit and then click the "Open" button to open the document in Adobe Acrobat XI. Locating the Removing White Margins option is not as straightforward as it sounds because the option is not present in any of the menus.
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Click the "Tools" button in the upper right corner of the window and then click the "Pages" node to expand it. Click the "Crop" option in the Manipulate Pages section to select the tool. The cursor changes to a crosshair.
Double-click anywhere in the document to display the Set Page Boxes window. From this window, you can control the margins of the PDF, as well as remove the white margins.
Check the "Remove White Margins" box in the Margin Controls section and then click the "All" radio button in the Page Range section to crop all pages in the PDF. The Remove White Margins option is available only when the "CropBox" option is selected from the "Apply to" drop-down box in the Margin Controls section.
Click "OK" to crop the pages of the PDF and remove the white margins. Scroll through the document to ensure the margins are cropped correctly and then save the changes by pressing "Ctrl-S." To save the cropped PDF in a different location, click "File" and choose "Save As" from the menu or press "Shift-Ctrl-S."