Hi there, userdjennings226.
Since QuickBooks Self-Employed can generate only one Schedule C categories, we're unable to add multiple companies on it.
If you'd want to, you can purchase QuickBooks Online and then sign up for a different accounts. From there, you can use the same credentials and switch company easily.
I've also added these links that have detailed information about QuickBooks Self-Employed:
We'll be right here if you have additional questions about the program. Have a great day!