A permanent press cycle on your washing machine or dryer is meant to remove and minimize wrinkles.
A washer on permanent press will wash clothes in warm water and rinse them in cool water, maintaining a mild agitation and spin. The warm water helps relax creases while the slow spin prevents new wrinkles from forming. A permanent press cycle is gentler than a regular cycle, making it good for synthetic fibers like polyester, rayon and knits. Because it does not use hot water, a permanent press cycle will also reduce shrinking and color fading.
A dryer on permanent press uses medium heat to smooth out wrinkles as it dries, while avoiding the high heat that can shrink clothes and fade colors.