This video helps you determine if your jacket has an integrated storage pocket and describes how best to stuff your jacket into it.
Some jackets come with a self-stowing pocket. This means the jacket is designed to pack up inside one of its pockets, which makes it more compact for storage inside a pack or car when it’s not in use. On many jackets, it’s the inside pocket, and you can tell this because when it's unzipped and flipped inside out, you can see a double zipper tab. This indicates that once it has been stowed in the pocket, you’ll have a zipper to close it up with and close it in. So you’re going to unzip the pocket and start turning the jacket into it, inside out, until it's completely stuffed inside.