Is it ok to left the foods remain in the socket when the wisdom tooth hole has completely covered?

Good hygiene : When the wisdom tooth is removed the roots leave a ‘socket’ in the bone. This hole in the gum may last for up to 3 months to heal completely. Care of the mouth is very important for proper healing. Good hygiene and proper wound care would be keeping the area clean.

Confused: If the socket "has completely" been covered, the food would not tend to accumulate in that area. Until then (and even after) one should brush and floss, and rinse to keep your mouth free of food debris and plaque that will cause a bad odor and lead to cavities and gums problems in and around the other teeth. The gums should close over in 1-3 weeks but full bone remodeling may take months.

Depends on timing: Not sure based on question whether the extraction was recent and or has been awhile and the tissues have healed over extraction site. It is best to keep the area clear of debris to facilitate healing after the removal. As time goes on, the bone will fill in and the depression will generally lessen with time.