External user as owner of site


I have a site where the gear box is not showing to add site permissions, because I want to add an external user as owner of a site along with me.  She is listed in Azure as guest user.

I have racked my head on how to do the following:

Am I able to add this external user as co-owner of a site in my system?  And how?

2 Replies
What role do you have in that site?

@Juan Carlos González Martín 


Owner, I'm also global admin