: Users can choose an "Ad-free subscription" to remove advertisements within the application.
It sounds like you're asking about (likely referring to the Adobe Acrobat Pro DC or a similar PDF tool, possibly a typo for "A-PDF" or "All PDF") and want to develop a feature in an English version.
Add 128-bit or 256-bit AES encryption, set user passwords, and restrict printing or copying. The English version uses standard security terminology (e.g., "Owner Password" vs. "User Password"), making it easy to understand.
(e.g., A-PDF Split & Merge, A-PDF Page Cut)