Per the FAQ:
Can I edit or delete my posts and threads?
Yes. You have 6 hours after posting to edit or delete the content. If you need something deleted or modified after that period, you can ask a moderator to remove or edit it via PM.
If it's been more than 6 hours and the edit button is gone, you can send a PM to a mod with your request if it's important to change. If it's just a typo or something minor, don't stress—everyone here is usually pretty understanding about those!
Hope you find everything you are looking for!