What should a person do if somebody elses mail comes to your address?

If someone else's mail arrives at your address, you should first check to see if it’s clearly marked with a return address. If it is, you can return it to the sender by writing "Not at this address" on the envelope and placing it back in the mailbox. If it continues to happen, consider contacting your local post office to report the issue. Do not open or tamper with the mail, as it is illegal to do so.