How can I vertically and center 3 buttons on my mobile site?

I am working out of wordpress. I have 3 buttons i would like to place on my mobile site. I would like for these buttons to be centered vertically in the middle of the page.

I don't really know how write this code the proper way , nor the css.

I want them to have a decent amount of space , so they wont be touching one another either.

Can anyone give me an example and the best way to code 3 buttons in html and be centered vertically in css?