Depth Of Field Photography With Point And Shoot Question About Photography ISO And Shutter Speed?

Question about photography ISO and Shutter Speed? - depth of field photography with point and shoot

I have a photo shoot outside today with an old camera

ISO 100 Shutter Speed 500

I also have a reading lamp ... His hand was halfway through reading the light that tells me I can take the game to this point

ISO-100 will be clearer and better than ISO 400

What is the difference?

ISO 100 affected my depth of field? As