For most users, completing the change online and printing the confirmation receipt is the most reliable method. However, a printable blank PDF (PS Form 3575) is available on the USPS website for those who wish to mail the form or keep a paper copy for their records.
Once you've printed the form, fill it out carefully and accurately:
If you search Google for "Change of Address," the top results are often advertisements for private companies that charge $40 to $80 to file the form on your behalf. They mimic the USPS website design.