Thanks for posting here in the Community, @plredistribution.
QuickBooks Self-Employed (QBSE) only allows one company (business) per subscription. For a second company, you'll need to sign up for a new QBSE account. This means each company you'll create will have its own subscription. However, you can use the same log-in credentials so every time you log in, you can just select the company you'll be working on.
Just a heads up, every QuickBooks account is charged. To manage your billing subscription, you can refer to this article: Update your QuickBooks Self-Employed billing and subscription details.
I can also help you out if you have other questions with QuickBooks Self-Employed. Just leave a reply below and I'll get back to you. See you again soon!