Eliminating sugar alone can help a lot since it increases fat growth. I'd say stick to a cardio workout, one that doesn't require the use of your hands like running.

Live healthy..eat healthy...no diet..
Ride bikes..dance...play sports..swim...lift weights..do burpees.
Get enough sleep...
Replace fake sugary foods ...with healthy fats like guacamole...laugh ...relax...have fun...

when you say arthritis I wonder is it your leg or any anatomy, when you exercise you may feel the pain. Many people above say about eating right food and be happy, to be honest I'm losing weight and lost 7kg. Is it based on what they say? Partly. But serving is important, more we take body absorb, when burn fat, it's not enough. Metabolism play major role. Vitamins can help to lose weight because it's supplement to body be active. I bought magnesium is to reduce cramp but then realize I lost weight. You need magnesium it help with muscle, it's muscle vitamins.

Honestly at that weight and height I’d say you just need to tone your abs. Maybe some light cardio... I wouldn’t change too much though.

just so you know, not everyone is capable of having a flat stomach. i've known girls with anorexia that held on to a little pooch well into an underweight bmi.

Do what exercises you can but you are not overweight, so don’t stress about a little belly.