Heat can be transferred from one place to another by three methods: conduction in solids, convection of fluids (liquids or gases), and radiation
Conduction- Heat flows through solids using conduction. for example , if you heat up one end of metal rod , another end would be warm up . here heat flows from one end of rod to another end through the molecules of rod. so in conduction, molecule passes heat to anothe molecule in contact and this way heat flows from one place to another place.
Convection- Convection is the heat transfer due to movement of molecules within fluids such as gases and liquids. for example- when you put a pan of water on stove to heat up. water molecules at the bottom of pan get heat up and become less denser so these molecules move to the top of pan and colder (denser molecules) move down to bottom of pan . this process keeps on untill whole pan of water heats up.