If you look at the sound hole of an acoustic guitar, you will see the structure of the body. There are braces and linings, which are essential for maintaining the integrity and playability of the guitar. The X brace is a sturdy and durable support, usually used for acoustic guitar because it is heavy and strong enough to withstand the pressure of steel strings.
On the body of the guitars, you will find the bridge. This is one end of the string. The strings are inserted into the holes, and the bridge nails fix them there.