Even though buoyant force act on us why can't we float on water?
This is due to buoyancy explained by Archimedes principle.
When we are in water the air in our lungs increases the volume of our body while our density remains constant.
Since our body density is almost equal to that of water we can float ( Humans are 65% water)
A body floats in water only if the desity is less than or equal to that of water.
Every human floats on water, or technically in water.
The reason why we sink when we drwon is due to water filling into our lungs which increases the density of our body, making it greater than that of the surrounding water.