Great question and one which many will benefit from. Jowls form from loose skin around the mouth, jawline and neck. Non surgical options include ways to tighten skin. The least invasive option includes Ultherapy, which uses micro focused ultrasound waves to heat up tissues deep to the skin. This causes collagen breakdown, with new collagen formation resulting in tightening of the overlying skin surface.
Other minimally invasive ways include a combination of ultherapy, with liposuction, laser skin resurfacing, facial fillers.
Pictures would be helpful to further determine what options would work best