Welcome to Community, @cuenca.
I was not able to see the option of deleting a company in QuickBooks Self-Employed. However, you can delete your data associate to your account and even on the application.
Refer to this article on how to delete your data: Delete all of your data.
Also, if you want to invite or remove an accountant in QuickBooks Self-Employed you can use this article: How to invite or remove an accountant in QuickBooks Self-Employed.
Let me know if I can be an additional help, have a great day, and take care!
