What would be the best procedure for a defined jaw line like kylie jenner?

Jawlines consist of an underlying bone structure and the soft tissue draped over the bone. Models/celebrity jawlines most often have a very positive bone structure with youthful natural overlying tissue. The key is the bone support. To that end, lipo is less ideal since it 'thins' the natural cushion soft tissue - focus on small but defined enhancement of the jawline/bone structure with thin implant strips. 

Liposuction under the jaw would take care of the subtle double chin.  However, microlipo of the face and jaw angle would be needed to better define the jaw.  Also, a chin implant would be a consideration.  Seek out a consultation with a board-certified surgeon.  Best wishes.