The phrase "paper mail" refers to letters, cards, or documents that are sent using traditional physical mail services rather than electronic methods. It means sending messages or information on paper through the postal service. Full definition
Or you can pay your taxes by paper mail with a check, money order, or cashier's check. (irs.com)
No need to waste time in line waiting for paper mail or detailed payment history. (800loanmart.com)
Depending on the carrier, some steps in applying for or updating policies are only done via paper mail or on the phone, while some are done online. (policygenius.com)