You can train your cat to walk on a leash with a lot of patience and a few simple rules. A harness is best for a cat. Cats won't respond well to jerking their collar so a harness is really best and should be loose and comfortable for the cat.
First, allow your cat to play with the new items so she gets used to them. Try putting the harness on her and see how she reacts. This step is very important, if you force the cat to wear the harness, they are not going to be happy at all with the harness or with you. Take your time with all the steps. If your cat balks at any step, go back to the previous one. It is a lot harder getting a cat to cooperate than it is for a dog.
After the cat is wearing the harness loose, then it is the time to tighten the harness up until it is the right fit for the cat. At this point, you will want to give the cat time to wear the harness. Next attach the leash. Then you will want to start walking the cat inside, until the cat is doing well. Once the cat is comfortable with the leash then it is time to go outside for a walk.
When walking with the cat make sure there is not too much loose leash or they will be running in all random directions. There are many distractions for a cat outdoors - birds, squirrels and the neighbor’s pets might cause your cat to want to run around, but you must keep a tight leash so that your cat walks with you and is not dragging you all over the place. You will soon be enjoying your outings.