How should a woman with istihadah (irregular bleeding) purify herself and manage the bleeding while fasting in Ramadan?

Summary

A woman with istihadah must wash her private part, bind it, and perform wudu after the prayer time begins for each obligatory prayer, then pray promptly unless delayed for a prayer-related benefit such as covering the awrah or waiting for a congregation. While fasting, she is not required to insert cotton or a tampon, because an insertion passing beyond the inner limit of the vagina can break the fast. It suffices to bind the area with a sanitary pad or similar covering, following the order of washing the private part, changing the pad, then performing wudu.

Written in our own words from the original fatwa — check the source before acting on it.