I appreciate your time posting here, @christophe-picha.

I've come to ensure you can invite your accountant to QuickBooks Online (QBO).

To guide you with all the steps mentioned above when inviting an accountant to your account.

Here's how:

1. Sign in on your QBO account as a primary admin and go to the Gear icon.
2. Select Manage users under the Your Company column.
3. Click on the Accountants or Accounting Firms tab.
4. Enter your accountant's email address and select Invite.

Once invited, your accountant will receive an email about the invitation. You'll know they accepted your request when the status from the Manage Users page shows as Active. 

For more detailed information, visit this article: Add accountant users in QuickBooks Online.

Moreover, client invites expire after 30 days. If an invite is close to or over 30 days old, advise clients to delete the original invite instead of resending it: What to do if you can't accept client invites in QuickBooks Online Accountant

I'll always be here if you need anything else about connecting with your accountant. Feel free to add them in the comments below. Take care!