HP LaserJet Pro 500 Color MFP M570 - Manual (Page 129)

3. Touch the Fax Setup menu.
4. Touch the Fax Set-Up Utility button.
5. Follow the on-screen prompts and select the appropriate response for each question.
NOTE: The maximum number of characters for the fax number is 20.
NOTE: The maximum number of characters for the fax header is 25.
ENWW Setup for stand-alone fax 115