Military insignia on a uniform denotes rank, membership in a branch of the military, such as the Air Force, or membership in a particular unit, special authority like the military police, duty assignment, or prior service in a branch of the military, according to Olive Drab. If you are making a WWII uniform you will need to sew the proper insignia on it to make sure you have the right rank, branch and assignment for the uniform.
Choose thread that is the same colour of the WWII insignia so the thread does not show up when you sew the insignia on.
Thread sewing machine with the thread and pin the WWII insignia to the uniform in the place you want it to sew it. Place the pin in the middle of the insignia so it does not get in the way of the sewing machine’s needle.
Place the uniform and insignia flat under the sewing machine needle. Position the needle so it will fall right inside the outer edge of the insignia.
Sew the WWII insignia onto the uniform with a medium length straight stitch and normal tension. Sew slowly to ensure you get around every edge of the insignia properly. Stop sewing and turn the insignia at every corner before you start sewing again.
Remove the uniform and insignia from the sewing machine and cut off any loose threads.