Enable Document Rights - Government Documents

The problem is legal rather than technical. Yes, it's possible to remove security from a PDF (though not with Acrobat), and then apply Reader extended rights using Acrobat Pro - however if the owner of the document (the USFG) has deemed for whatever reason that they don't intend to allow such things, you'll need their permission to alter the document. Copyright or lack thereof in Federal material aside, bypassing a "security feature" on an electronic document without permission is a breach of the DMCA.

You may be in luck with government issued documents. As UVSAR said it would be a illegal to modify this document if it was from the private sector. But, about every document produced by the government is in the public domain. If you think about it all government documents were paid for by your tax dollars so they belong to you. Most of the time the document are "certified" by the government to let you know that they came from the government and not someone else.

Actually I don't think the government can copyright a document:

With one exception, works of the United States government are
public domain. 17 U.S.C. 105. The only exception is for standard reference
data produced by the U.S. Secretary of Commerce under the Standard
Reference Data Act, 15 U.S.C. 290e.

State governments are different, but you are usually always safe with Fed documents.

Forms may need to be protected from alteration of the text because of legal restrictions involving the wording of the form. There is no reason one could not scan and OCR the form.

I know the IRS requires vendors of tax forms and tax software developers need to have their forms approved by the IRS prior to being able to distribute them or use them.