How do I add QB as a third party admin. for MA withholding tax?

Hi, @ChanceGardener. 

I've got all the steps to help you add QuickBooks as your third party agent in Massachusetts. Here's how:
 

1. Sign in to the Massachusetts Unemployment Insurance site.
2. Select Additional Services.
3. From Access Management, click Manage third-party administrator access.
4. Choose Add third party administrator.
5. Hit Next.

Refer to this article for more about the complete process: Authorize QuickBooks as your Massachusetts unemployment Third Party Agent.

Moreover, you can visit this comprehensive guide on setting up QuickBooks Online Payroll to automate your tax and form management: Set up QuickBooks Online Payroll to pay and file your payroll taxes and forms.

Please drop your comment below if you need further assistance adding QuickBooks as a third-party admin or have any QuickBooks-related concerns. The community team is available 24/7 to answer them for you.