Welcome to the QuickBooks community! It's great to have you with us and I love that you're diving into using QuickBooks Self-Employed. I know working with a new product can take some getting used to and when you're not sure what steps to take, the QuickBooks support teams are here to help.
As our most simplified version of the program, QuickBooks Self-Employed also keeps customer information simple. Unlike the Online and Desktop versions of the program, Self-Employed doesn't create a customer profile where you enter things like a business name separate from the client name. However, it is possible to add their address, which you can do in the Client info section on an invoice transaction.
This section is directly under the Client name and Client email fields, and if you're not seeing the boxes where you'd enter the address, try clicking the Client info tag to expand the section. Learn more about creating an invoice here: Create and invoice in QuickBooks Self-Employed
If there are other details you'd like to include on the transaction, you can use something like the Message box at the bottom of the invoice to include those details.
Another option you can consider is switching to QuickBooks Online or QuickBooks Desktop. Depending on your needs, these may work better for you. Starting with either of these programs would mean starting fresh as there isn't a way to transfer data from Self-Employed at this time. I encourage you to check out our All QuickBooks Products page to learn more about QuickBooks program options and make sure you have the best fit for you.
I hope that helps! Feel free to get back in touch next time you have questions. Enjoy your day!