Android
Open the Google Play Store app .
Tap Menu. My apps & games.
Tap on the app or game.
Tap Uninstall.
Iphone
Start the Settings app.
Tap "General," and then tap "iPhone Storage."
Scroll down to see the list of apps installed on your iPhone, arranged in order from largest to smallest.
Tap an app you want to uninstall.
Tap "Delete app," and then confirm you want to delete the app by again tapping "Delete app" on the confirmation window that appears.
Note: On Iphone app may be backed up to cloud so to permanently delete:
From the Home screen, open “Settings“.
Choose “iCloud“
Select “Storage“.
Select “Manage Storage”
Select your device.
Scroll down and select “Show All Apps“.
Turn the app on or off as desired.
Tap “Turn Off & Delete” when prompted, and you're done.