Welcome to Community and thank you for posting here in our forum. I'll provide the detailed steps to ensure you're able to add your newly hired accountant to your QuickBooks Online.
To start with, I suggest going to the Gear icon and choose Manage users. From there, you'll have the option to enter the accountant's name and email address to start adding them.
Here's how:
Sign in to your QuickBooks Online company.
Click on the Gear icon and choose Manage Users.
Go to the Accounting Firms section.
Enter your accountant's email. Then, click Invite. They will receive an email with a link for signing in to your company.
They will be asked to create a user ID before signing in the first time unless they already have an account with Intuit Business Services.
Until your accountant signs in, their status on the Manage Users page is "Invited." After accepting the invitation, their status changes to "Active."