Interactive video units computerized merchandising systems that offer convenient, electronic shopping without the need of salespersons - are selling Americans a widening variety of products from shoes to cosmetics, according to a report issued here.

To use them, a customer simply touches an infrared video screen for an audio and video presentation of what is offered, notes Intermark Corp. Once a selection is made, the screen and a printout tell the customer where in the store that product can be located.In addition to being used in kiosks, smaller units are also apearing as shelf-edge computers right at the point of sale.

Industry estimates are that some 200,000 of the shelf-edge units will be in retail stores by 1990.