 So you just want to split, not a problem. Split allows you to left click on a polygon and divide it into more topology. This works on quads, it works on tries. As usual, if you hold alt, you can plan your targets ahead of time and this option works exceptionally well when used in conjunction with the point split action when you want to extrude a shape from a face. Hope that helps and as always, hope you have a fantastic day and I'll see you around.