If you accepted the invitation, your account has already become a member of your family group. Check here: https://account.microsoft.com/family/home?fref=home.cards.card.family.persona
How to switch from Microsoft Personal to Microsoft Family
I have recently been invited to a Microsoft Family group. Currently I have a Microsoft Personal account that I use mainly for the OneDrive as I have a lot of pictures. I also have a Microsoft account through my work laptop, which provides the apps like word etc. I can't seem to work out how to switch my Microsoft Personal account to the family account? Some people have told me I should open an app like word and click 'change license'. However this won't work for me as all the apps come through my work Microsoft account which I can't change. How can I update my personal account just by going through my onedrive?