How do I delete my Pinterest account permanently, and does it remove all my pins and boards?

Go to Pinterest, click the down arrow top-right > Settings > Account management > 'Delete account' at the bottom. Pinterest sends a confirmation email, click the link in it to finalise. Everything, boards, pins, follows, is scheduled for permanent deletion. There's a 14-day grace period where the account is deactivated and you can reactivate by logging back in, but after that it's gone for good. If you only want a break, use 'Deactivate account' just above it instead, which hides your profile but keeps your data. Cancel any ads or business billing first if you have it.

Note the difference: 'Deactivate' hides you but keeps everything (reversible), 'Delete' wipes it after 14 days (permanent). Pick deactivate if there's any chance you'll come back.