Thanks for the query.
Bleeding for 3 months since delivery is not normal and something to be of concern.
First of all get a urine pregnancy
test to rule out pregnancy.
Once pregnancy is ruled out get a transvaginal ultrasound
to detect any retained products of conception. It is most common cause for prolonged spotting per vagina.
You need to consult your Gynecologist for further work up.
Hope this helps.