When you’re out mountain biking you need a semi-flexible cycling shoe that offers grip and protection from water. Most mountain bike shoes include a space in the sole of the shoe where you can fix an SPD compatible cleat.
SPD is the system of clipless pedals that you twist your foot out of. The cleat lies flat in the sole of the shoe and as such doesn’t interfere with your walking. If you don’t want to use clipless pedals then you can still use the same mountain bike shoe but without the cleat fixed into the sole.
If you buy a pair of shoes with laces, after doing your laces don’t forget to tuck the bow inside the laces or use a lace band if the shoe has one. This keeps stray shoelaces out of the way of your chainset.
Mountain bike shoes can look much more casual that road shoes so if you don’t fancy the competitive cycling look that shouldn’t be a problem!