How do I enable and use SMS as Two-Factor Authentication method?

Please Note

It is not possible to re-activate authentication via SMS once it has been replaced by a permanent security device, including an online security card.

Additional Information

Why is my phone suddenly not receiving SMS Messages from IBKR?

How can I change the mobile phone number where I receive the authentication codes?

Do I need to reactivate IBKR Mobile authentication if my phone number has changed?

How do I login using the Digital Security Card+?