Greetings, goldensun13.
I'm here to share some details about having more than one company on an account.
The ability to add multiple companies on a single sign-in is only available in QuickBooks Online. Right now, the QuickBooks Self-Employed account only supports one business.
Since this product is designed to track your transactions from self-employment, this can only handle one company. I recommend you send feedback straight to our product development team to ensure we meet your business needs.
You can send your feedback directly through this link:
https://selfemployed.uservoice.com/forums/242769-general
If you have further questions about QuickBooks Self-Employed, don't hesitate to let me know. I'll be around to help you out.