How do you switch from one POV character to another without confusion while writing a novel?

The best way is start a new chapter. And make it immediately clear that the POV has changed. If Chapter 1 is from Susan’s POV, start Chapter 2 with something that makes it clear right away that we’re inside somebody else’s head. For example, “After six beers, Jeff felt like throwing up.” Or “Serena groaned in frustration as steam poured from her car’s engine compartment.”

Another way to change POV is to have scene break signified by asterisks * * * and a few line breaks. Then make it immediately clear that we’re in somebody else’s head.

Don’t try to change POVs without using a chapter break or scene break. That’s called “head hopping” and will only confuse the reader.