Our 3D socks are designed to primarily function outside of a shoe, although they can also be worn in some shoes. They generally fit into casual and lifestyle shoes. Fit is dependent on the shoe design, how much room is in the toe box, and how tight you wear your shoes. Similar to over-the-counter insoles, it may help to remove the existing insole to improve fit.To wear them in shoe, its best to place them in the shoe first, then slide your foot in place. You do the opposite to take them off, removing your foot first. They will not work in all shoes, but for some it definitely helps. They really shine for the times you need more than a sock but less than a shoe.