The Geneva Convention is like a big rulebook that lots of countries agreed to follow when they are fighting in a war. It has many rules to make sure that soldiers and ordinary people are treated fairly during the war.
For example, one rule says that soldiers can only fight other soldiers, and they should not hurt people who are not fighting like children, women, and doctors. Another rule says that if someone is wounded, they should be taken care of, no matter which side they are on. A third rule says that prisoners of war should be treated well and not be tortured or hurt.
The Geneva Convention was first created in 1864 to help people who were hurt during war, and it has been updated many times since then to make sure it deals with all the different types of wars and weapons we have today. It is very important because it helps to protect people during times of war so that they can be safe and not get hurt unnecessarily.