Can I text people from Denmark from Canada?

Why don't you Skype?

I would suggest you ask Virgin Mobile and she asksTelia. There might be a price difference depending on what company you have. It might also be dependent on what contract you have with your company. And the prices might vary from country to country.
I guess you are talking about mobile phone and not sending e-mail from your PC

I would just punch in the code to get out of Canada (011) plus the country code for Denmark (45) then the number of the mobile phone (8 digits)

Like this (the first 2 digits are the carrier)

20-xx-xx-xx
31-xx-xx-xx
40-xx-xx-xx
42-xx-xx-xx
50-xx-xx-xx
53-xx-xx-xx
60-xx-xx-xx
61-xx-xx-xx
71-xx-xx-xx
81-xx-xx-xx