Your son worked as an independent contractor for Door Dash, so he has to pay self-employment tax for Social Security and Medicare, as well as (maybe) ordinary income tax depending on how much he earned. And he needs to prepare a Schedule C to enter his mileage, etc. as a business expense. The online version of Self-Employed is expensive. He might be able to use Free File if he qualifies:
If you qualify to use it, there is another full-featured free version of the software:
Try Free File:
You qualify if your income was $39,000 or less, or $72,000 or less if active duty military, or if you qualify for Earned Income Credit
https://ttlc.intuit.com/questions/1900583-what-is-turbotax-free-file-program
https://ttlc.intuit.com/community/self-employed/help/what-is-the-self-employment-tax/00/25922
https://ttlc.intuit.com/questions/2902389-why-am-i-paying-self-employment-tax
https://ttlc.intuit.com/questions/1901340-where-do-i-enter-schedule-c
https://ttlc.intuit.com/questions/3398950-what-self-employed-expenses-can-i-deduct
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**