How can I achieve a more masculine jaw and angular lower-face? (photos)

There are several procedures which can help. You could do one procedure at a time or all at once.Facial liposuction- helps remove unwanted fat in the double chin and lower cheek area.Chin implant- a round or even better a square chin implant will help bring the chin forward.Mandibular angle implants- help add more definition to the back of the jaw.Buccal fat pad removal- helps to create more definition under the cheek. If you want to try on the look of an implant, you could have a hyaluronic acid filler such a s Voluma to the chin and back of the jaw.

Thank you for your pictures.  In my opinion, you may benefit from neck liposuction.  Please consult with several board certified plastic surgeons for the most accurate recommendations.

 The photographs demonstrate a weak and recessive chin profile, for which a chin implant can improve. Chin implants are placed through small incision underneath the chin to give added projection and width to the chin area and mandible. Chin implants are placed under local anesthesia as an outpatient procedure the takes approximately 30 minutes. For more information, diagrams, and many examples, please see the link and the video below

You would need jawline augmentation with a chin and jaw angle implants combined with fat removal through neck liposuction and buccal lipectomies and perioral mound liposuction. You would need the total 'package' to get the best possible result in a rounder face like yours.