AFAIK, you can't, anymore. I'm unsure why the option to delete your own threads was removed.
You also can't report your own threads so a moderator can see your request to delete it.
Your best bet is to replace the title and body with something like a period, so it's mostly blank, then lock the topic.
(this subforum is for technical support relating to Bitcoin, not the forum)
It's been years since you could delete your own topic...
grondilu deleted the whole "What will governments do against Bitcoin?" thread, which had diverged more into a philosophical debate about politics.
I removed the "Remove own topics" permission for regular users. I didn't know they could do that. It would be OK if it only deleted if it only has your own posts in it, like if you accidentally posted in the wrong place.
At the same time, I enabled "Move own topic".
I think that you can report your own posts.
