When you train your dog to unzip your jacket, not only will you be working on a complicated and useful task, but you'll be increasing the bond you have and establishing yourself as his leader. This is a difficult trick with many parts, but when he figures it out, you both will be so proud.
Before you attempt this trick your dog must already know basic obedience and be clicker trained. This is an advanced trick and you need to be sure your dog is ready and has a strong foundation for learning. Give yourself plenty of time and only train in short sessions. End each section on a good note, without pushing too far or letting your dog get frustrated.
Below are three different methods you can try to teach your dog to unzip your jacket. Read through them to decide which one will work for you and your dog. With time and consistent training, your dog will be able to give you a hand when your own hands are full.