In Jain Dharma, the difference between Jīva and Ajīva is fundamental:

1. Jīva

• Jīva means a living soul.
• It has consciousness (chetanā).
• It can know, feel, think, and experience karma.
• Jīva is found in all living beings, from one-sensed beings to humans and celestial beings.
• Because of karma, the soul is bound in the cycle of birth and death.

2. Ajīva

• Ajīva means non-living substance.
• It has no consciousness.
• It cannot know, feel, or experience anything.
• Ajīva includes things like matter (pudgal), space (ākāś), time (kāl), dharma dravya, and adharma dravya.
• These are all supports of existence, but they are not living.

Simple difference

• Jīva = conscious, living soul
• Ajīva = unconscious, non-living matter/substance

In short

• Jīva has life and awareness.
• Ajīva has no life and no awareness.

If you want, I can also explain this in very simple Hindi/Gujarati or in a table form.