How can I automate MAC Address spoofing?

When I installed macchanger on Ubuntu 20.04, it asked whether I wanted macchanger to run automatically. I selected yes. Then I successfully spoofed my wired network interface MAC address to a random address. I expected it to be randomized automatically since I selected "Yes" to whether I wanted macchanger to run automatically, but the MAC address was back to the original permanent address when I turned the computer on the next day.

Edit: [Information on what I'm doing](https://itsfoss.com/change-mac-address-linux/).

address mac mac address privacy spoofing