Jīva, in Jainism, means a living being or an individual soul. Just like you, every living being from tiny insects to big elephants has a soul. This soul is very important because it is what gives life to that being.
Now, imagine that every soul has a unique color. Some souls are yellow, some are blue, some are green, and so on. These colors are called karmic particles, and they stick to your soul because of your thoughts, words, and actions. Just like how you might get dirty if you play in the mud, you get these karmic particles stuck to your soul when you do good or bad things.
These karmic particles can make your soul heavy, just like how carrying a heavy backpack can make you tired. This is important because if the soul is heavy, it cannot progress or evolve. This means that the soul will have to be born as a living being over and over again until it is freed from its heavy karmic particles.
The goal in Jainism is to remove all the karmic particles from your soul and become free from the cycle of birth and death. This is called achieving moksha, and it is the ultimate goal for every living being.
So, in short, Jīva is the soul of every living being that has unique karmic particles stuck to it because of its thoughts, words, and actions. The goal is to remove all the karmic particles to achieve moksha or ultimate freedom.