Article: Tap the icon that resembles two silver gears to open the Settings menu. It's next to a grey icon with a single gear. This displays how much storage space is being used on your iPhone or iPad and how much space each app is using. All apps installed on your iPhone or iPad are listed at the bottom of iPhone/iPad Storage menu.  Tap on the app who's data you want to delete. The amount of space an app is using is listed to the right of the app.  Look for apps that use the most amount of space that you are not longer using. It's the red text at the bottom of the info screen.  This displays a confirmation pop-up menu asking if you want to delete the app. Alternatively, you can tap Offload App to delete the app and keep documents and data related to the app, in case you want to install it again with your saved information. It's the red text in the lower-right corner of the confirmation pop-up.  This deletes the app an all related documents and data. This will be a fresh install of the app without all the accumulated documents and data the app may have built up.
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Open the Settings  app. Tap General. Tap iPhone Storage or iPad Storage. Scroll down and tap an app. Tap Delete App. Tap Delete App. Reinstall the app from the App Store.