my iPhone 7 is switching on and off< I was told its software problems. how do I update it if it cannot go on

what were you doing when this happened did you delete something or were you trying to update; if you are 100% SURE its software issue connect it to a computer and update from iTunes hope you have fast internet.BACKUP YOUR STORAGE BEFORE if posible.

I think that if its a software issue iTunes will force you to restore and update.

Whopever told you that is mistaken, hardware problems are the most likely, usually battery.

Perform the following and then have it looked at by Apple

Give those steps a try.

If your iOS device restarts or displays the Apple logo or a spinning gear unexpectedly

then if that does not help you will need apples help

https://getsupport.apple.com/ and or https://www.apple.com/retail/geniusbar/

tenson

tenson means what?