Hi
If you are generally an active person involved basically in a lot of walking, jogging and running then there are high chances that its normal wear and tear.You should not be worried about the click sound as in most cases it is not a sign of any disorder.
ADVICE
I would recommend knee strenghthening exercises and till your knee gets really strong use a knee support while walking.
Avoid sitting on low surfaces and on the floor.
Avoid walking on uneven surfaces and wear proper shoes while walking.
Next Steps
Take a break from stressful activities for sometime and concentrate on knee strenghthening.
Health Tips
Use a knee cap while walking