Hello, chace7.
Yes, a cell phone number is required for QuickBooks Online. QBO uses the cell phone number to send important notifications, such as security alerts, account updates, and password resets. It is also used for two-factor authentication to enhance the security of your QuickBooks Online account.
I suggest you check out the Account management page, where you can conveniently handle and edit your personal and company information in QuickBooks.
Let me know if you need further assistance in managing your account. I'm here to help you. Have a great day.