Can I use my own font on the address part of my mailer?

Unfortunately, no.

The USPS recommends the following fonts for your direct mailer.

• Arial Black
• Copperplate
• Courier/Courier New
• Helvetica
• Lucida Fax
• Lucida Sans
• OCR-A
• OCR-B-MT
• SF Sans Serif
• Tahoma

Full information can be found here: https://about.usps.com/publications/pub177.pdf