How do I save my open office work so that I can Use it on a Microsoft office computer?

Hi
Im currently doing my coursework and at home I have open office but on the school computers it is microsoft word so which option should i pick so that I can Access both of them. Just to make it clear I’m saving it form my laptop (open office) .
Thankks in advance
I mean which option should I select when it says "save as file type" so that its compatible on both?