If I forward an email to someone, and then forward it someone else..

[BettyHumpter]

Can the first person I forwarded the email to see that I've forward it to someone else?

Hope that makes sense lol

Not unless you cc them.

No, as long as you forward the original separately to the other person.

No.

However if you forward a calendar/meeting invite the organiser sees that it has been forwarded.

Emails do nest, so you may need to remove a bit.