I am having the same issue. I have paid for a Family Premium subscription but there is no "2. Click Premium for Family in the menu on the left." as the instructions indicated in the support page for Invite A Member.
I have attached multiple screenshots to show the non-existent menu option and other screens where community members have suggested I look to find the invite option.
I have logged into my Spotify account in IE and Chrome, both updated to the latest versions with no luck. I have tried to view the menu on my mobile browser on my Android device (Samsung S8 Active) to no avail either.
I'd appreciate any help in getting this resolved, thank you!