Yes, on Reddit you can edit posts and comments. However, you can only edit a post’s content and not its title.
Once you edit something, an asterisk will appear next to it to tell other redditors it’s been changed.
If you have more questions that aren’t covered in these FAQs, check out r/help. Someone may have had the same question, or you can ask a new one and a Reddit administrator or one of your fellow redditors will help you out.