There is a green substance coming from under the vehicle near the front passenger door what is it? door

It is hard to determine with a leak could be without physical hands on inspection. This could be brake fluid -- as brake fluid will travel under the vehicle to the rear wheels, and when aged, can have a green tinge to it. If this is brake fluid, it would be a serious safety issue that would warrant discontinuing driving until repaired. It would be a good idea to have this evaluated as soon as possible.