For example if I want to insert $\bar{x}$, it is simply typing \bar{x} in LaTeX.
In Onenote and other MS office products, you first type Alt+= to enter the math environment, and after you type \bar, what is the next keystroke I'm suppose to press so that I can type $x$ under the bar?
I have tried many combination, including {, (, space, tab. None of them work, they just skip the part under the bar.