A company list will be added to the sidebar in the macOS, Windows & Android app in the next update.
This list is visible if the user has 2 or more companies - it will not be visible if there is only one company.
Clicking a company in the list will make it the active company.
I have not found a nice way to add this feature to the user interface of the iOS app, so the company selection will remain in the "My company" tab. If someone has a good suggestion on how it can be improved, please let me know