The TOTP token is a time based token. You can paste a secret key or have the server generate the secret and scan the QR code with a smartphone app like the Google Authenticator or FreeOTP turning your smartphone into an authentication device.
The server will create the OTP key and a QR Code will be displayed to you to be scanned.
The Google Authenticator only supports an OTP length of 6.
The Google Authenticator only supports the SHA1 algorithm.