You are suffering from hormonal changes causing Androgenetic alopecia causing hair fall. It's completely stoppable even regrowth of hair is possible with certain medications without any side effects. Treatment depends on the grade of hair loss. So, it's a must for diagnosing which grade, you are in for an effective treatment. Please  send photos of your head, by direct online consultation for accurate diagnosis and proper treatment.

You can get dermal fillers done on the temporal area to give a sharp and a less broad forehead look

Yes in females also hair transplant works great to reduce the size of the forehead.

Your full face needs to be evaluated. We can’t look at only forehead. It is possible to reduce the broad forehead by adding some hair in the thin part of hairline

Hello dear. Your hair and forehead look fine. No treatment required.