Follow these steps to clear out the Safari cache:

1. Press Settings > Safari.
2. Scroll down and tap Clear History and Website Data.
3. Tap Clear History and Data. 

Soft Reset (old method)

1. Press and hold the Home button (big circle below the screen) and the Sleep/Wake button (on top of the iPhone) simultaneously. 
2. Hold both buttons until the iPhone shuts off and begins to restart. 
3. Let go when you see the silver Apple logo appear on the screen. 
4. You've just performed a Soft Reset!

How to Hard Reset iPhone 7 or iPhone 7 Plus

   1. Press and hold the Lock/Wake button on the right side of your iPhone.

   2. At the same time, press and hold down the Volume Down button on the left side while keeping the Lock/Wake button pressed.

   3. Keep holding both the buttons until the screen turns black and then switches back on to display the Apple Logo.

   4. Wait for a couple of seconds until your iPhone boots up completely and displays the Lock screen.

That's all you need to do to force reset your iPhone 7 or iPhone 7 Plus. The method is quite similar to older iPhone models, except that you have to hold the Volume Down button this time rather than the Home button.

Apple® iPhone® XS / XS Max - Restart / Soft Reset

A restart (soft reset) can resolve issues like continuous resetting/rebooting, device crashing, freezing, won't ring or vibrate, can't make or receive calls, device locks up, and keypad doesn't respond.

 A soft reset (turning the device off then back on) is similar to restarting a desktop computer and is one of the first steps in troubleshooting a device. A soft reset won't affect data on the device.

 Caution:

• Emergency SOS in iOS 11 provides you with the ability to contact emergency services (e.g., 911) using the same button combination as a soft reset. 
• If you hold the Side and volume buttons for longer than 5 seconds, your iPhone automatically calls emergency services. Visit the Emergency SOS support page for more info.

1. Press and hold the Side button (top right edge) and either Volume Button.
2.  If the phone is off or not responding, refer to soft reset for an unresponsive iPhone.

    2. When "slide to power off" appears, release buttons.

    3. Slide the Power switch right.

 Allow several seconds for the device to power off.

    4. With the device powered off, press and hold the Side button until the Apple logo appears, then release.