This wear is due to over pronation of your foot. Pronation happens naturally to absorb impact of walking, your foot ‘rolls’ slightly from the outside to the inside.

It’s quite a common thing for runners to have to deal with, obviously if you’re running you’re doing more footsteps and putting more stress on your feet, it can lead to leg hip and back pains etc if not dealt with. I have a slight over pronation and use structured running shoes to correct, but don’t need anything for my ‘normal’ footwear.

Your picture suggests you’re pronating more than you should, I see from another comment you’ve made an appointment to get it looked at which is good. The likely outcome is you’ll need structured insoles to help make your foot movement more neutral.