Are there specific criteria for eligibility for a hair transplant?

In my family, the men on my father's side
It's a sad situation that hair loss is hereditary.
So when I was young, all the grandfathers
I actually thought he didn't have any hair.
Anyway, I am a woman, and only my hair
I take after my mother's side of the family, so I'm less worried about hair loss.
The problem is that my dad has also been like this since he was young.
My hair is thin, so it makes me sad every time I look at it.
To undergo hair loss treatment, the entire hair
How much should be left?