Noncovalent interactions are like hugs between the molecules. Just like when you hug your family or friends, molecules can also hug each other without actually staying together forever.
There are four main types of noncovalent interactions: hydrogen bonding, van der Waals forces, electrostatic interactions, and hydrophobic interactions.
Hydrogen bonding is like a special kind of hug between molecules that have hydrogen and oxygen or nitrogen atoms. They hold hands and share their love for electrons.
Van der Waals forces are like a weak hug between all molecules. They happen when molecules get close to each other and their electrons wiggle around which causes a very weak attraction.
Electrostatic interactions are like positive and negative friends that stick together. If a molecule has a positive charge, it can hug a molecule with a negative charge.
Hydrophobic interactions happen when molecules that don't like water (like oil) get together and don't hug molecules that do like water (like salt).
All of these hugs are important in nature and help things like your body work properly. They're called "noncovalent" because they're not like a wedding ring that binds molecules together forever, but more like friendly hugs that come and go.