Within 24 hours, you will receive a “Move Validation” email. You must click the link in that email to activate the forward. Simultaneously, USPS sends two physical letters:
You can no longer simply mail a paper form to the post office and expect it to be processed automatically. New security protocols require every applicant to prove their identity through one of two methods: In-Person Verification: If you use a physical PS Form 3575
The most critical update isn't on the form itself, but in how you find it. The USPS has issued warnings regarding private companies that charge excessive fees to file a change of address on your behalf.
The most critical change in recent years is the mandatory for all change of address requests. Mail carriers can no longer accept paper forms directly, and you can no longer print the form from your home computer to mail it in. Standard Forward Mail & Change of Address - USPS