Creases are inevitable. As soon as you slip your boot, slipper or sneaker on, your foot alters the shoe forever. Perhaps not immediately, but take a few steps and you'll see what I mean. The way your foot rolls from heel toe and then repeats bends your toes and thus the toe box, creating creases wherever the material folds.
If the shoes you're wearing are made from leather, good luck getting the creases out after a few hundred wears. They've dug pretty deep by then, depending on how rough you've been on them. But you're not to blame. Creases are completely natural — an unavoidable annoyance that comes with wearing (and breaking in) any pair of shoes. Plus, you can (probably) remove most evidence of them ever happening in the first place. Think of removing the creases as something you can do as often as you clean or shine your shoes.
How to Get Creases Out of Shoes
Assess the damage done. Clean your shoes if they're dirty. Remove the laces and stuff each shoe with a shoe tree, ideally with a solid cedar upper. You can use a cheaper material like newspaper or cotton towels, too. Make sure the shoe is shaped and stretched to its original, or desired, silhouette. The toe shouldn't be curling upwards and the creases should be level again.
Grab an iron and turn it to the cotton — or medium — setting. It should not be too hot, as scorching the leather can damage it or cause discoloration. Let the iron rise to the proper temp.
Dip a cotton hand towel in warm water. Ring it out. It really only needs to be damp. Lay it over the shoe, covering the impacted area.
Gently press the iron to the damp cloth, never holding it for too long on any one spot. Press and slide the iron over the creases.
Once you're finished, remove the damp towel and turn off the iron. Keep the shoehorn, newspaper or other material (whatever you stuffed inside the shoe during step one) in the shoe overnight. If there are cosmetic issues you need to fix, feel free to wax or shine your shoes.
Do not wear the shoes immediately after heating because the creases will return more easily as the leather is more malleable.
Repeat as needed. Or, order a pack of crease protectors. Typically, you get a set of two — one for each shoe — for under $10 dollars. They slip attached inside the toe box, right above your foot. I tried a set in my Air Force 1s and could barely feel them.