changing buttons

I’d like to change the size, font and color on my buttons on my pages. Can anyone tell me how to do this? For example, I’d like to make the button that says “sign up” on this page: https://feelbetteryoga.com/teacher-training/
to be larger, red and rectangular with font that matches the rest of my page.
I also don’t know how to realign the buttons- right now I can only have them as their own line of text- I’d like to be able to have them aligned with other text.
Help!
Also still looking for a good widget plugin that will allow me to create buttons for the global content part of my site. Do you know one??