Hello, my friend.
"Password"? I assume you mean keyphrase/keyword. Well, first of all, the keywords you're talking about are not difficult
And yes, if you use "in" it won't matter. In fact, go for natural word flow, since it's better for UX, and that's what google likes. Additionally, you don't have to use the whole keyphrase in H-tags. If possible - sure, if not - just do it in content naturally. Google has very-very sophisticated AI, so no worries, they will understand what page is about.
Just don't go overboard with keyword stuffing. 
