The code is a mailto link, which every phone understands. You choose the address and, if you like, the subject and a starting message such as "Quote request from the flyer". That line tells you where the enquiry came from, no tracking needed.
Keep the message short: every character becomes dots. A subject and one sentence keep the code small enough for a business card.
Questions
Does the person need an email app?
The phone opens whatever handles email on it, usually Mail or Gmail. If none is set up it will ask them to set one up.
Can I see who scanned it?
No, and that is the point: nothing sits between the scan and their mail app. You simply receive the email.