Need to change user name and password

I can help you change the username and password in QuickBooks Online, @userinfo48.

You can make adjustments to your accounts from your Intuit Account Manager. Here's how:

1. Sign in to QuickBooks Online.
2. Choose your profile icon next to Settings ⚙.
3. Select Manage your Intuit Account. This opens the Intuit Account Manager.
4. Click the Sign-in & security menu.
5. Choose the User ID, Email Address, or Password section.
6. Make your changes, and once done, click Save.

You'll want to update customer's information. Feel free to check this article: Change your business name, contact info, or Companies House Registration Number (CRN) in QuickBooks ....

Let me know if you have other queries in managing your account. I'll be happy to help you. Have a safe day.