[sign up] vs. [sign me up], what's the best way to name buttons?

1. Why is sign up bigger than sign in?
2. Which button is clicked to register to a new account?
3. What is button in website?

Why is sign up bigger than sign in?

A person has to be a member of the site before they can log in. Thus most websites promote the button for signing up more than the login button, making it easy to actually sign up.

Which button is clicked to register to a new account?

Login | Register: This would explain clearly what the button's function is.

What is button in website?

Buttons convey a specific call to action (CTA), like “Submit” or “Pay.” Buttons tell users, “if you click me, something will happen.” Designers also use buttons to communicate with users through states, color, and text.