Hemming a jacket sleeve is a common alteration that can be done to adjust the length of the sleeve. It involves folding up the excess fabric at the bottom of the sleeve and sewing it in place to create a clean and finished hem. This alteration can be done by hand or by machine, and it is a relatively simple process that can be completed in a few steps.
There are several reasons why you might need to hem a jacket sleeve. The most common reason is to shorten the sleeve length, which can be necessary if the sleeve is too long and bunches up at the wrist. Hemming a sleeve can also be done to change the style of the jacket, such as to create a more fitted or cropped look.