You'll enter your password
Whenever you sign in to Google, you'll enter your password as usual.
You'll be asked for something else
Then, a code will be sent to your phone via text, voice call, or our mobile app. Or, if you have a Security Key, you can insert it into your computer’s USB port.
During sign-in, you can choose not to use 2-Step Verification again on that particular computer. From then on, that computer will only ask for your password when you sign in.
You'll still be covered, because when you or anyone else tries to sign in to your account from another computer, 2-Step Verification will be required.