When a lid is placed on a pot of boiling water, the drops of water that form on the inside of the lid are a result of condensation. The process of condensation occurs when water vapor, which is in a gaseous state, comes into contact with a cooler surface and transitions back into a liquid state.
In the case of a pot of boiling water, the water molecules near the surface of the boiling water are heated and evaporate, turning into water vapor. When the hot water vapor contacts the cooler lid, which is at a lower temperature, it loses heat to the lid. As a result, the water vapor condenses back into liquid water droplets on the surface of the lid.
The reason we often observe more condensation on the inside of the lid rather than on the pot itself is because the lid is typically cooler than the pot. The lid is in contact with the cooler air surrounding the pot, allowing it to cool down more quickly. As a result, the water vapor in contact with the lid loses heat more rapidly and condenses into droplets.
This phenomenon is similar to how condensation occurs on the outside of a cold glass of water on a hot day. The warm, humid air comes into contact with the cold glass, causing the moisture in the air to condense and form droplets on the glass surface.