Guides

Plain-English guides to mailing documents and letters that need proof, and to sending real mail from your AI agent.

Documents and mail that needs proof

Certified mail · 2 min readSend certified mail onlineTracking and proof of delivery, without the post office.Taxes · 2 min readReply to an IRS notice by certified mailAnswer a tax notice with a dated delivery record.Housing · 2 min readSend a security deposit demand letterAsk for your deposit back, with a signed receipt.Credit · 2 min readMail a credit report dispute by certified mailDispute a credit report error by mail, with proof.Small business · 2 min readSend a demand letter for an unpaid invoiceA formal payment demand when emails go unanswered.Documents · 3 min readMail a PDF onlineUpload a document; we print, envelope and mail it.

Send mail from your AI agent

AI agents · 3 min readHow to send a physical letter from ClaudeConnect Sendpaper to Claude and have it mail real letters and postcards.

Looking for a ready-made prompt?Browse use cases: birthday cards, landlord notices, tax replies and more, each with a prompt to copy →

Sendpaper prints and mails what you or your agent writes. We're not a law firm or tax preparer and don't give legal or tax advice; for deadlines and the right address, check the notice itself, the agency, or a professional.