As a Salesforce admin, they can change the initial order in which apps appear in the Lightning Experience App Launcher. Users can then reorder their personal view of the App Launcher to their liking.
All apps installed in the org appear on the app menu items list. However, the apps that users see in their app menu and App Launcher vary depending on each app’s visibility settings and the user’s permissions.Users see only the apps that they are authorized to see according to their profile or permission sets.
You can also reorder the app in classic version by following the same steps.