This explains how to:
Your accountant must have a Sage Accountants subscription to receive an 'accountant' invitation. If they don’t have a Sage Accountants subscription, add them as a user or ask them to upgrade to a Sage Accountants subscription.
Invite an accountant using their Accountant ID
NOTE: If your accountant hasn’t provided their Accountant ID, follow the steps to help them find and share it with you.
Select the Invite Accountant tab, then select Invite an Accountant.

Select Next, confirm the invitation, then select Yes, Send Invitation.
After you send the invitation, wait for the accountant to accept it. When they accept, Sage will connect your subscription to your accountant's subscription.
To check an invitation status, go to the Invite History section.
In Invite History, you can remove an accountant connection or view the status of outstanding invitations.