When you swipe something, you move it in a sweeping motion, like the way you swipe your credit card through a reader. Swipe can also mean "to steal," like when your little sisters swipe the cookies you baked before they cool.
You might swipe at the mosquitos buzzing around your head at a summer picnic, or swipe your finger across a touchscreen to sign for a purchase. When used to mean "steal," swipe is a gentle kind of verb: it's not quite "burglarize," but closer to "sneak off with." This newer meaning comes from American prison slang, first appearing in the 1880s.