To farm Wintry Bell you must go to Gorges of Spirits in Wuthering Waves. This Wintry Bell farming guide will show you the farming routes of Wintry Bell and the node locations.

Below are screenshots of some of the Wintry Bell node locations.

There is a vendor located at Jinzhou Main City

You can buy up to 15 Wintry Bell at this vendor

Credit to WILDMAT7 for latest farming routes.