The fabric that is used to cover the edges of the quilt, batting, and the backing is called the quilt binding. When you bind a quilt, it helps to secure the borders and also makes the quilt look better. A binding is the last step to making a quilt. Any fabric can be used for binding; it can be something that you have already used to make the quilt or anything else that will enhance the design. It is better to have two layers of fabric rather than one to make it more long-lasting.
Find below step-by-step instructions on binding quilts.

Calculate the strips: Check the size of your quilt and then double it. Add 10’’ more to the corners and seam, divide by 40” to get the total number of strips that you will need.
Stitch: Two strips are placed perpendicular to each other and stitched diagonally. Cut the backing and batting that are extra even before you start to string the binding together. If you have any seams that are in the corners, you should move them so that seams are not in the corners. Fold the edge of the binding so that it faces the quilt and put it in the front so that you have a gap of about 8”. The end of the quilt should be next to the binding. Start sewing from the front of the quilt and allowing a difference of a quarter inch. Stop stitching just before the corner.
Hand stitching: The binding should go behind the quilt and keep it in place use clips before you stitch it by hand. Using a needle to sew the binding and knot it at the end, you can use two threads to ensure it is firmly held. The stitch should be done only with the batting and backing and remove the extra yarn. Continue the same process across the length of the quilt, and you do with binding the quilt.