This is the Central Regulatory Domain Agent for Linux. It serves one purpose: tell the Linux kernel what regulatory rules to enforce for 802.11. CRDA is no longer needed as of kernel v4.15 since committing 007f6c5e6eb45 ("cfg80211: support loading regulatory database as firmware file") added support to use the kernel's firmware request API which looks for the firmware on /lib/firmware. Because of this CRDA is legacy software for older kernels. It will continue to be maintained. CRDA is a udev helper for communication between the kernel and userspace. You only need to run this manually for debugging purposes. For manual changing of regulatory domains use iw (iw reg set) or wpa_supplicant.
