Welcome to Healthcare Magic.
You probably must be having male pattern hair loss.
It is usually hereditary.
You can confirm the diagnosis with a scalp biopsy.
There are medications available like topical minoxidil and oral finasteride
which are very effective in male pattern hair loss.
Alternatively, there are many surgical options also available like hair transplantation
You can consult your Dermatologist
for confirmation of diagnosis and prescription of medications.
For hair transplantation, you may have to consult a cosmetic surgeon.