How to Unlock PDF Form
Adobe Acrobat allows you to create, edit, fill out and print PDF forms. So long as you're the author of the form, you can apply various security levels to prevent unauthorized editing and printing of the form. Basically there are two levels of security for opening the document, and to edit or print it. Using the security settings, you can lock and unlock the form anytime.
Open Acrobat Reader or Acrobat Pro. When the application starts, go to "File" and "Open." Navigate to the PDF form that is to be unlocked. Then click "Open." If the form has been protected with a password, you will see a "Document Open Password" prompt on the screen.
Type the form's password in the respective field, and click "OK." Now the form will open.
Go to "File" from the top menu and click "Properties." Now the "Document Properties" dialog box will appear on the screen. For checking the current security restrictions, open the "Security" tab and see the "Allowed" and "Not Allowed" restrictions in the dialog box.
Click "Change Settings." Now you will be prompted for the "Permissions Password." In the "Enter Password" text box, type the password and click "OK." Once the Settings dialog box opens, click the "Permissions" tab and un-check the box next to "Restrict Editing and Printing of the Document."
Press "CTRL" and "S" to save the document. The unlocking settings will not apply until the document is saved, so click "OK" to confirm. Now the PDF form will be unlocked and you can edit or print it.