Change oil and leak is not coming from plug or oil filter. but when car is parked there is oil on the right side on the floor?

Change oil and leak is not coming from plug or oil filter. but when car is parked there is oil on the right side on the floor?
What kind or Vehicle? Check around the oil pan first to see if the gasket is intact. Also look at both ends of the engine to see if it is coming out of one of the main seals(typically will drip more when running).