Can I order an additional sim card and give it to my friend as a gift?

Yes you can
https://fizz.ca/en/faq/how-do-i-order-sim-card

And where is your referral code
https://fizz.ca/en/faq/how-do-i-invite-friends-to-join-fizz

You only have to activate your SIM when you want. The SIM has its number and don't work when not activated, so you can order one, and give it to your friend, he will be able to activate THIS specific SIM card upon payment. He will just be able to use his phone quicker then.

@Andrej,
Yes can do that, I did it with my friend and it works , don't forget, there is a 35$ bonus till 15th of June
Regards
Mo