honeysingh,
if your friend is a green card holder, then visa is not required. If an H1B holder, then visa is required. Invitation letter content is as follows
The letter must include the following information about the person being invited
1. Complete name
2. Date of birth
3. The person's address and telephone number
4. your relationship to the person invited
5. The purpose of the trip
6. How long the person you are inviting intends to stay in Canada
7. Details on accommodation and living expenses
8. The date the person you are inviting intends to leave canada
The letter must also include the following information about yourself
1. Complete Name
2. Date of birth
3. address and telephone number in Canada
4. Occupation
5. Whether you are a Canadian citizen or PR
6. A photocopy of a document proving your status in Canada
This is only a guide. You must write the letter of invitation yourself. Hope this helps.
