I've set up 2 different Microsoft 365 accounts, personal and business and not sure what to keep. I cant get the business account to show my email, keeps adding onmicrosoft.com. Can anyone help please?

I've set up 2 different Microsoft 365 accounts, personal and business and not sure what to keep. The bus one isn't that much more and I do have a business, inactive at the moment. There a lot of features I dont need like the web service, domains, all very confusing to set up. I set up the domains through google domains, but I guess it was chance to squarespace. I cant get the business account to show my correct email, keeps adding onmicrosoft.com. Now I dont know how to get rid of it and if there's a benefit to keeping it over the personal. Can anyone help please?