Open the Settings app
Go to Apps or Applications
Select the app manager (or Manage apps)
Tap Filter or Sort options
Choose Show hidden apps (or Disabled/Hidden apps, if available)
Enable the hidden app (or tap Unhide)
If the app is disabled: go to Disabled apps and tap Enable
Check the Home screen/App drawer for hidden or restricted apps
Disable any app-hiding features in the launcher settings (if used)
If using parental controls: open the parental controls app/site and allow the app
If using a work/profile container: switch to the correct profile and unhide/enable the app there