The Administrative Procedure Act (5 U.S.C. § 500 et seq.) governs:
It explicitly states that agencies
shall give interested persons an opportunity to participate in the rule making through submission of written data, views, or arguments . . . .
Traditionally, people submitted comments to proposals by mailing letters to the specific agency addresses provided in Federal Register notices. Now, agencies also solicit and accept comments by email and through the Internet.
The site also includes: