Many of us come across Acrobat PDF documents which are locked by the authors so that you cant perform some actions on the file which may be copying ,printing or editing them .If you have any such document and if you want to remove restrictions on it freely, Go to the link below.
To unlock a PDF file, enter it's location in the "PDF file to unlock" field ( shown in the figure) , either manually or by clicking on the "browse" button.
Click on ' Submit ' and the unlocked version of the PDF will be displayed in a new browser window, opened in the default PDF application for your system (usually Adobe Acrobat Reader) .
Note that this utility works only for acrobat documents which are not read protected .
There is one more link which opens up your PDF file for editing.Visit PDF Filler.
Are you looking for some free desktop application to unlock your PDF document ? Then use PDF unlocker.
Once you complete the installation , just drag the .pdf file to the "PDF Unlocker " icon on desktop and Your restrictions will be removed.
Note : If a document is password read protected , For removing these restrictions , you need to know the password before hand.