When it comes to software, you always click, "hitting" and "pressing" are physical actions,but software is strictly virtual so you always "click" a button in a software.

Press or hit a key but always click a button on the software.

So in your software manual, when you are specifying physical actions, like maybe using the keyboard than press or hit both can be appropriate eg. press the Enter key or hit the Enter key.

But in a software I feel click or select feels most appropriate eg. click the Refresh button or Select refresh

When it comes to software, you always click, "hitting" and "pressing" are physical actions,but software is strictly virtual, so you always "click!" a button in a software.

You may Press or hit a key but always click a button on the software.

So in your software manual, when you are specifying physical actions, like maybe, using the keyboard, then "press" or "hit", both can be appropriate eg. press the Enter key or hit the Enter key.

But in a software I feel click or select feels most appropriate eg. click the Refresh button or Select refresh