How is it administered meaning in the muscle or other and what is it still effective if administered inappropriately

I think the doctor or nurse would administer it correctly.
I use to get the shot more than 10 years ago.
They gave it to me in the hip every 3 months.
It's not 100% effective even if administered correctly (no BC pill, shot, patch, etc is), but I never had any problems with it.
I liked it.