Type 2 diabetes is the most common form of diabetes, affecting the body's ability to properly process blood sugar. It is a chronic, progressive disease where the body becomes resistant to insulin or does not produce enough insulin. Common symptoms include frequent urination, excessive thirst, hunger, fatigue, and blurred vision. Tests like fasting glucose, oral glucose tolerance, and A1c can diagnose type 2 diabetes. Treatment involves lifestyle changes, oral medication, or insulin depending on the individual case.