No, procedure does not leave any cut/incision/scar/wound. You will not get any marks as it's a vaginal procedure.
In-clinic MTP procedures are common and effective, and millions of people have gotten these MTPs safely. Unless there is a rare and serious complication that’s not treated, there is no risk to your future pregnancies or to your overall health.
Yes, it is 100% legal before 20 weeks of Pregnancy.