Usage patterns
〈物〉にしわができるwrinkles/creases form on something
Wrinkles have formed on this shirt.
しわが寄るwrinkles gather or form (on skin, cloth, etc.)
Wrinkles gather around my eyes when I laugh.
しわを取るto remove wrinkles
I removed the wrinkles with an iron.
しわを刻むfor wrinkles to be etched (into a face, etc.), often used figuratively
Years of hardship have etched wrinkles into his face.
Expressions
皺を伸ばすsmooth out wrinkles; straighten out; relax