Capital One credit card applicants for application.capitalone.com. If you received a letter from Capital One with an invitation to apply, then you were invited to apply for a credit card.
The mail offer should have included a 16 reservation number, and a 6 digit access code (this is a lot of digits!).
Pre-qualified for a card does not mean you are approved. You will need to fill in the application and wait for a response.
To apply, visit www.application.capitalone.com, enter your codes and apply for the credit card.