What does a website know about me (my bot)?

Lets say I want to automate an account creation process, what are factors that the website where I create the accounts on, can find out about me/my bot? And what are red flags for websites that I'm a bot, besides using the same IP address?
Can they also find out my MAC Address as an indicator that I'm botting even when I change my IP every time I create a new account?

Thanks in advance for your help!

This post summarizes some of the key ways: https://www.blackhatworld.com/seo/how-your-browser-is-tracked.1239703