Hide the icons on the ninox app

Yes

if you don't want to show permanently,  then you can untick them 

in form edit mode you will see these options on the left of the form 

if you don't want them on selected forms etc.

then as far as I know you need to use CSS/Html hacks

I've seen this on the forum so will try an find a link for you

this might give you a clue to some of them

https://forum.ninox.com/t/g9hrtf1