What is the story of Safa and Marwa? What is Safa and Marwa in the Quran?

What is the story of Safa and Marwa?
What is Safa and Marwa in the Quran?
What is the ritual of Safa and Marwa?
What to do during Safa and Marwa?
About
Safa and Marwa are two small hills, connected to the larger Abu Qubais and Qaiqan mountains, respectively, in Mecca, Saudi Arabia, now made part of Al-Masjid al-Haram. Muslims travel back and forth between them seven times in what is known as saʿī ritual pilgrimages of Ḥajj and Umrah.