Let me share additional input, @Mark2929.

Yes, @MichelleBh is referring to the same email you've received. You review the steps below to ensure that you have link your QuickBooks Desktop company file to your existing Intuit Account.

1. Open your QuickBooks company file.
2. Login using the Admin credentials. 

3. Having logged into the QuickBooks Desktop Company file with the Admin user credentials, the Intuit account window displays the following prompt:

   • You’re the admin: Choose this option if you are the individual who met the credentials listed in step 1. Enter the email you have or want to associate with the Intuit account for this QuickBooks Desktop Company file. Skip to step 3 below.
   • You’re not the admin: As defined above, but you are logging into the file with a shared Admin user credential. QuickBooks closes the Intuit account prompt and will remind you again in 7 days. 
4. Choose You’re the admin and enter the email address associated with your Intuit account. ​​​​​​​
5. Enter the password associated to your existing Intuit account  on the Sign in window displays.
6.  The Intuit account window closes after you successfully login to your existing Intuit account Intuit account. This account login is now considered the Primary Admin for the Intuit account.

To addressed your second question, yes it will not affect your desktop and payroll accounts. Just make sure to log back into the Intuit account, detailed in the steps above, every 180 days.

Feel free to leave a comment below if you have other questions. I'm always here to help.