Is there a way to include a postal barcode so as to print on envelopes for the zip code?
I’m assuming you are talking about US Postal Service zip code 5+4.
Check their webside ribbs.usps.gov. They have some add-in for MS-Office and also much much more for free. I do not think just a Font would do it.
Link from @horst of the future here to fonts, etc…: Printing postal bar codes on envelopes
Correct! https://ribbs.usps.gov/index.cfm?page=intellmailmailpieces. This is the actual resolution to the dilemma of the missing/lacking feature in many/any word processing application on most platforms.