Which is the most common body part to get a blood clot (why is it so and how to avoid this)

Blood clots, medically known as thrombosis, can occur in various parts of the body. These are small gel-like masses that control bleeding and internally they stop the flow of blood leading to life threatening situations.
The most common site is the deep veins of the legs. This condition, called Deep Vein Thrombosis (DVT), can have serious health implications if not promptly diagnosed and treated. It happens when the blood in the veins does not move fast enough.
The deep veins in the legs are particularly susceptible to clot formation due to several reasons.
The legs are farthest from the heart, requiring the veins to work harder to return blood against gravity. Reduced blood flow or stagnation can lead to clot formation.
Extended periods of inactivity, such as long flights, bed rest, or sedentary lifestyles, can slow blood flow in the legs, increasing the risk of clotting. Trauma to the legs or surgical procedures can damage blood vessels, triggering the body’s clotting mechanism as a natural response to injury.
Cancer, heart disease, obesity, and certain autoimmune disorders can elevate clotting risks, especially in the lower extremities. Pregnancy, hormone replacement therapy, and birth control pills can increase clotting risks due to elevated estrogen levels, affecting leg veins more prominently.
A study in 2018 highlighted the link between tall height and blood clot. "Taller people have a greater venous surface area and possibly more venous valves, allowing for a greater area in which thrombi can form. Indeed, the majority of thrombi form in valve pockets of the deep veins in lower limbs where blood flow is stagnant," the researchers said.
Another study published in 2017 in the journal Circulation: Cardiovascular Genetics had also found a link between blood clot and height. The researchers found that men whose height was under 5 foot 3 inches had a 65 percent lower risk of VTE compared with men who were 6 foot 2 inches or taller.

Immediate medical attention is required if you notice:
Preventing DVT involves lifestyle adjustments, medical interventions, and awareness: