Glucose-6-phosphatase converts glucose-6-phosphate to glucose

Muscle tissue lacks glucose-6-phosphatase enzyme(this enzyme is present in liver) so it cannot convert glucose-6-phosphate to glucose

Glucose-6-phosphate, which is release from muscle glycogen, will goes to liver and converted to glucose.

So muscle tissue cannot directly contribute for blood glucose, it's need help of liver enzyme for coversion from glucose - 6 phosphate to glucose.

Glucose-6-phosphate undergoes glycolysis in muscle tissue to produce ATP for muscle contraction

Muscle does not contain glucose 6 phosphatase enzyme thus glycogen can not be converted into free glucose and released into circulation.

Unlike muscle glycogen, Liver glycogen has glucose 6 phosphatase serves as storage and can be converted into free glucose and released into blood circulation and maintain blood glucose levels.