A guitar strap is a strip with a leather or synthetic leather piece on each end to hold a guitar by the shoulders. A guitar strap is made at an adjustable length to suit guitarist most comfortable position. Electric guitars have varying accommodations for attaching a strap.
The most common are strap buttons, also called strap pins, which are flanged steel posts anchored to the guitar with screws. Two strap buttons come pre-attached to virtually all electric guitars, and many steel-string acoustic guitars. Strap buttons are sometimes replaced with "strap locks" which connect the guitar to the strap more securely.
The lower strap button is usually located at the bottom or bridge end of the body. The upper strap button is usually located near or at the top or neck end of the body : on the upper body curve, at the tip of the upper "horn" (on a double cutaway), or at the neck joint (heel).