You can either add a payroll plan or not and then click Checkout.
Enter the same email address, mobile number, and password.
Then click One More Step and then choose Sign in.
Click Yes, that's correct.
Then enter your billing info to Get started.
Once done, you can then have two businesses when you log in to QuickBooks. Then if you want to switch to the other company, you can click the Gear icon on the top right. Then select Switch under Profile.