Most people use keys in their everyday life.
So using keys is something people generally understand.
Physical tokens such as FIDO2 keys (which you usually plug into a USB port) are a good example.
Alternatively, You can install Authentication apps on most phones that can generate one-time codes.
To obtain the code, you must have the device with the app installed and configured.
Some examples of login tokens:
RSA SecurID
The RSA SecurID product is a key-fob that provides a one-time passcode (OTP) which, when combined
with a PIN, becomes the login secret.
This solution requires that the server and the key-fob keep close sync with their time.
Universal Two Factor
Another key-fob-based authentication mechanism is to use a Universal Two-Factor (U2F) token.
One such token is a Yubikey.