How do you unlock a circle shaped key hole?

To unlock a circle-shaped keyhole, you typically need a corresponding key designed for that specific lock. Insert the key fully into the keyhole and turn it clockwise or counterclockwise, depending on the lock's mechanism. If you don't have the key, alternative methods like picking the lock or using a bypass tool may be necessary, but these should only be attempted on locks you own or have permission to access. Always consider contacting a locksmith if you're unsure.