Deleting items from your iPhone that you are sure you won’t want to access later helps save memory. To delete an app you are no longer using, all you have to do Is press on the app’s icon until it starts to shake. At this point, you will see a little cross pop up on the top left of the icon, just press on that to delete the app. If the cross doesn’t show up, then that means it’s an app that was installed by Apple and the uninstall feature has been disabled for that app so it can’t be removed.
If you want to delete text messages or emails, just slide your finger to the right or left on the item and then press Delete when it shows up. Then, to delete images, select the image you no longer want and tap on it to display the image options. When the options come up, tap on Trash and then Delete Photo.
To delete voicemails to free up a significant amount of space on your iPhone if you have been saving them, tap on the phone icon, tap Voicemail in the bottom right and look for “Deleted Messages”. When you see “Deleted Messages”, tap on that and a new screen will appear where you can tap on “Clear All”. That will permanently delete all your voicemails from your iPhone that had been deleted before.