Since you are essentially performing driving services for
both Doordash and Uber, it would make sense to report all of your income from
the driving service on a single Schedule C instead of trying to separate them.
Even though your income is coming from two different sources, you are still performing the same type of service. Then, if you start performing that same service for yet another company, you are all set and would simply include that income as part of your business income as well.
