This is useful if you have an older phone and have not yet added a phone number to your account.
Letter: You can also activate the DigiD app with a letter.This is only possible if you have added your telephone number to your DigiD account. Sms-code: You will receive the activation code by SMS if you choose to skip activation with ID-check or if you are unable to activate with ID-check.And a Dutch ID (passport, identity card or driver's license issued after November 14, 2014)