Hi
With a blood glucose testing machine.
Your doctor may give you one from your surgery if he or she thinks its needed but most of them don't like T2 testing themselves.
I was T2 for 2 yrs I'm now T1, I ended purchasing my own they are quite reasonable priced and testing strips.
I was given a new one yesterday from my doctor but being T1 it's key to have one, but it helped me when I was T2 knowing what food effected me