You can indeed. You have a 24 hour edit window as a Basic member, and you can also Delete any of your posts whenever you like. 
Both options are found at the bottom of every one of your posts. The edit feature is the little pencil, and the delete function is under the three dots (…). Tap that to expand your options, and you should see a little dustbin.
If you try the Discobot tutorial out it’ll show you how to use both features (and some others too )