1. Press and hold the Home button twice rapidly to open the app switcher, which shows you previews of apps you've recently used but haven't dismissed.
2. To clear the Twitter app preview, swipe up.
3. Swipe upon individual applications, as you did with the Twitter app, to remove additional background apps.
Perform a soft reset or restart your iPhone 7 after deleting Twitter and other background applications to delete cache and data from apps and iOS for better functioning. Turn off your iPhone for roughly 30 seconds before turning it back on. Launch Twitter once the iPhone has completely rebooted to verify whether it is operating correctly this time. If the programme continues to crash or fails to load correctly, go on to other possible remedies.