Mobile phones are in essence, tiny, but powerful computers.
And like a computer, sometimes they don't work exactly as they should.
This can sometimes mean you need to switch your device on and off again to fix the glitch.
But how do you do this on the Galaxy S21?
What is a soft reset, and why you might need to use it
A 'soft' reset, as suggested above, is turning your phone off and on again.
It differs from a 'hard' reset in that your phone isn't wiped, and you don't lose your data.
You would use this option if your phone isn't working quite as you might expect, for example if it freezes, or an app keeps crashing.
So how exactly do you carry out a soft reset?
How to perform a soft reset on the Samsung Galaxy S21
Step 1 is to press and hold the Bixby button on the side of the phone, until the screen switches off.
Your Samsung Galaxy S21 should automatically reboot.
When it restarts, it may ask you to enter your PIN to unlock the phone.
Once you have unlocked the phone, your S21 has been rebooted, and the soft reset is complete.