The best types of cardio to aid in weight loss are either low-impact, low intensity cardio, and weight training. It is important to realize that cardio is the third most important variable during a weight loss phase. The most important variables are 1) eating so that you are in a slight calorie deficit and 2) weight training to increase your metabolism and prevent muscle loss.
Increased daily steps count
Note that many of these are low impact and can be done at low intensity. This is actually recommended when you are looking to lose fat and preserve muscle mass.