Obtain invitation letter

I need an invitation letter for my friend to travel to Montenegro for business purposes, but I do not know anyone there. How can I obtain an invitation letter and what is the best way to go about this?

I have Canadian citizenship and will travel to Montenegro soon, my friend is Jordanian and in Jordan. We have been told we need an invitation letter for him. Could I make him one, while being there, and how long would the procedure for him getting a tourist visa take.

Thanks!

Elias15, to clarify: you are coming for business purposes and are entering with your Canadian passport visa free. Does your Jordanian friend wish to enter as a tourist (and your companion) or is the Jordanian in question also coming for business purposes, hence in need of an invitation letter from the business entity inviting him for a conference, business event, etc?

P.S. A Jordanian citizen can enter Montenegro visa free as a tourist for up to 7 days if in possession of  a valid Schengen, US, UK or Irish visa.