It's good to see you here in the Community, @maren1.
You'll be seeing a new login interface from the Employees menu when you integrate a third-party app, like KeyPay. Let me discuss this to you in details and help you log in successfully.
When you integrate a third-party app to process payroll in QuickBooks, you'll be asked to log in using the third-party credentials. With that being said, your QuickBooks login will not work.
But if you're having issues logging in using the third-party credentials, it could be the 3rd party cookies haven't enabled. I've got you the article with the steps depending on the browser you're using: Enabling 3rd Party Cookies.
You might also want to check out this article to get started with QuickBooks Online Payroll.
Feel free to leave a comment below if you have any other concerns. I'll keep an eye on your response.
