indeed, if you just ask over to google your question you will get straight answer about the difference between 2.
To give a quick answer to your question, yes they do the same thing and they are very similar. Burp is a hard core pentesters tool, you should have very good knowledge in security matter when you are dealing with.....ZAP has got some neat features, covers most of the bases but not all functions that burp has, and it is easier to use, doesn't requires much knowledge, basic system background will be enough to deal with.
the next question?