Ich verstehe dich.
is it possible to add "oe" instead of "ö"?
Yes. The reason that is done is for when a person is using a keyboard that doesn't have the o umlaut key. Since my keyboard is American English, I have to write oe. (I also can't use number combos like Alt+023 etc on this laptop so that's not an option either). If you write oe, you will still be understood.
Thanks for the info ;)