There is a delete as part of the #nostr protocol, nip-09, but not all clients impliment it. I know Iris, amethyst, and snort do. Relays all *should* accept it, and either delete the event, or mark it as something that should not be viewed.

But, because of how things propagate out to relays it can take time for it to actually be removed from everywhere, if at all.

I'm currently testing it out with a post I did yesterday, and then deleted earlier today. So far it's not 100% gone, but I'm going to give it a day and clear all my caches and see if it's gone everywhere or not.

If you want to check you can look at my posts and see if you see it. It says it's test of the delete function and had a picture of me in a very colorful shirt.