As said in the question, I want to type one character over another. Like for example:
In the above sample, I would like to have the characters raised above one over another so that i can easily edit the above sample as "Saample" (for example), just by placing the cursor next to the "a" with "#" over and just type "a". The reason I give this editing use case is that I do not want to use equation editors and to treat 1/S as an equation without the dash.
I can use any web application and would only type a maximum of one or two lines of text.
My actual usage is to type Sanskrit characters as outlined in the SuperUser question How to type one character over another in Microsoft Word: