Ключевые слова: accounting, accounts, address, bill, billing, bills, bulk, buy, class, close, document, documents, due, envelope, envelopes, first, house, in, invoices, is, letters, mail, mailed, mailing, mass, massive, multiple, office, official, order, papers, pay, payable, paying, payment, payments, post, postage, postal, print, printing, rate, service, stamps, submit, submitting, usa, usps, work,