PDF Merge: Set Security for Text fields in PDF Document Template

In Adobe Acrobat Pro, text fields can be edited in merged PDF. To prevent this follow the steps listed below:

A. Set the text fields to Read Only.
1. Navigate to Forms menu, then click on Add or Edit fields.
2. Double click the text field or right click then choose Properties.
3. In the Text Field Properties window, under Common Properties > set "Read Only" to checked.
4. Hit Closed.
5. Repeat Steps 2 to 4 for each Text field in the PDF document.

B. Set the Security to prevent editing of fields in the PDF document.
1. Navigate to Advanced > Security > Encrypt with Password.
2. Choose Yes if a message box appears on the screen.
3. In the Password Security - Settings window.
3.1. Put a check for "Restrict editing and printing of the document. A password will be required in order to change these permission setttings."
3.2. Type a password in the Change Permission Password textbox.
3.3. Set Printing Allowed = High Resolution
3.4. Set Leave Changes Allowed = None
3.5. Uncheck the Enable copying of text, images, and other content.
4. Hit OK button.
5. Type your password again in the Confirm Password Permission checkbox.
6. Save your PDF document.

Note: Steps provided is based from Adobe Acrobat Pro Version 9