Thank You Greetings Where Should I Say Thank You If A Business Card Does Not Have An Address?

Where should I say thank you if a business card does not have an address? - thank you greetings

Just at a job fair and met a representative of the pharmaceutical sales. I wish him a thank you note, however, only your phone number, email address, and data. How can it? I send a thank you for your e-mail? and if so, should one of these thank you greetings to the Internet, or simply a message: Thank you for your time?