If you are positive that she will get a refund, then you don't really need to file an extension as the penalties for not filing on time are based on taxes owed. So, if she has a refund, then there will not be any penalties. But, it is generally best to file one just in case and you can do so quickly online.
https://ttlc.intuit.com/replies/3931358
Instructions for filing an extension -
https://ttlc.intuit.com/replies/3301811