How to manage an employees name from maiden name to married name and still maintain their profile.

Hi notch,

Thanks for posting in the Community! Let me share with you the steps on how to update an employee's name in QuickBooks. 

1. Go to Employees tab.
2. Select an employee.
3. On left menu, select Details.
4. Enter changes you need to make on the employee's profile.
5. Select Save.

Once done, you can submit a Tax File Declaration for that employee. To access the employee Tax File Declaration section:

1. Select Employees, then select the employee name from the home page.
2. Select Tax File Declaration under Employee Settings.

On your second question, you might want to check on your supplier list to check if you have set up a supplier profile for this one which is coming up as an employee. To check: 

1. Go to Reports tab.
2. Search for Supplier Contact List. 

You can also check this article for your reference: Add a supplier in QuickBooks Online.

Let me know if you have any other questions. I'll be around to help. Have a great day!