Specify which apps you want to assign to this profile which can be accessed by the user in the app menu.
Setup > Manager Users > Profiles (Select a profile) Custom Sales Profile
Click Assigned Apps: Here you decide the visibility of apps in the app menu.
We can see list of all the apps. Select one default app. Default app appears when users log in for the first time. Select visible for any other apps you want to make visible. Currently users has access to Sales and Marketing app.