password protect your pdf file with 2 level.

__Prevent unauthorized viewing and editing of PDF documents__
1. Document Open Password—The document cannot be viewed without the password.
2. Permissions Password— The file cannot be edited without password
You can lock the following permissions with password

1. Print the PDF document
2. Insert, delete, or extract pages
3. Fill in existing form or signature fields
4. Copy or export content from the document