Admins can resend an invitation from the web console.
Navigate to [Organization] > [Users] and click on "Invite list", from there you may view the pending users that have yet to complete their account verification process.
If the verification period for the link has expired, click "Resend" to send a new invitation with a valid link.
Please refer to the following article for more details:
Manage User Accounts in Business Organization for Admin - Manage the role of each user