If by Acrobat writer you mean Acrobat Pro or Standard, there is not a way to automatically add usage rights to documents. It is intentionally a manual process in Acrobat. If you need to automate adding usage rights to documents, you'll need to use Adobe's LiveCycle Reader Extensions server-based product.
It's not clear to me what you mean by "permanently". There is an expiration date for the digitial certificate that's used to validate usage rights, whether they were added with Acrobat or LiveCycle Reader Extensions. With Acrobat 9, Reader-enabled documents are valid until some time in 2023.
Thanks George. I do mean Acrobat Pro. I wanted to be able to give the ability to Reader users to have extended Features (enable reader users to save form data or make commentaries) on all PDFs they open without someone from Acrobat Pro having to Extend the Features on that particular document.
That's not possible, sorry.