What type of button is this?

What type of button is being used in this picture?

I've been trying to replicate the result shown in this image by using radio buttons (so only one can be selected) but I've been struggling a lot to make the radio buttons both square and contain text. So far my buttons at best look like this:

Are there any simple ways of achieving the first result shown?

(Link for button I'm trying to replicate: https://www.poppyraffle.org.uk/?seg=WFMWEBPPC&gclid=Cj0KCQjwlN32BRCCARIsADZ-J4ugFDkJWk0d_x_pLSIfm6TY_jiLEilxDN99-vzeIIOg3Ls5lHv6Rm4aAljPEALw_wcB&gclsrc=aw.ds)