Sorry I have been unable to delete due to lack of knowledge.
It's always a good idea to include a link to the post you're asking about.
Normally there's a list of possible actions under the tags, opposite your user card. Here's the moderator list, and not everyone will have all these options; but delete is included where it can be.
While the Delete button/link should be under your post using the website [using the app it probably won't be], there are restrictions.
In particular, people with less than 20k rep need to wait two days to remove a question. If a question is worth asking, it's worth answering. Since you asked the question, it must be worth asking. If you have a change of heart, you need to wait and see if anyone will in fact answer it. If there aren't answers which disqualify it from deletion, you can delete it once the time limit has expired.
After the time limit, with less than 10k rep you can only delete your own question if there is at most one answer and that answer has no upvotes. That restriction is there because people have worked on answers which the community have thought to be worthwhile. Just because you're no longer interested in getting answers to your question should not allow others to lose the rep they have gained through their own work.
Members of the community who have the post-delete privilege (at least 10k rep) can still vote to delete the question if it warrants it. It takes at least three votes, possibly more.
Note that vandalising a question is very bad practice and will normally result in the question being reverted. That's far too complicated to do here (where the edited question has been migrated, and the migrated question is useful), but this question should not be regarded as a precedent.