Because the different path TBc took, is possible for this feature to not be released to the public.
The "My Stuff" section allows you to share with other players the list of all your units, items and companions.
By default, your data is indexed and can be viewed by anyone by using the Search bar you see on top of each page; you can deny other players to look for it by unchecking the appropriate option on Settings menu.
For now, if you want to share your roster with other players, you can do it by using the web app Terra Battle Stats: create a new TBS account by clicking here, add the characters you own in this page and then share them by going on 'Characters' > 'Share your Roster'.
Currently the only profile available on the Compendium is mine, you can see here a preview of what your page will look like: Silver Mitsuki *
* this is a preview of a function NOT under active development; once completed it will include more features.