The International Office staff does not provide letters of invitation. Invitation letters from U.S. universities are not required for visa applications, and often do not help the application.
You can read more at the U.S. Department of State website, including the following important quotation
"Visa applicants must qualify on the basis of the applicant's residence and ties abroad, rather than assurances from U.S. family and friends. A letter of invitation or Affidavit of Support is not needed to apply for a visitor visa. If you choose to bring a letter of invitation or Affidavit of Support to your interview, please remember it is not one of the factors used in determining whether to issue or deny the visa."
However, if you still wish to write your own letter of invitation, be sure to include the following information of the person you are inviting:
- Full name as it appears on the passport of the person you are inviting:
- Passport number:
- Country of citizenship:
- Date of birth written out (ex. January 1, 1976):
- Dates of travel:
- Address in home country:
- Reason for trip (for example: "I am graduating on X date and would like my mother to attend the ceremony.")
- Relationship to you (ex. Father, sister, cousin, etc.)
Give the letter to your person you are inviting so that they can include with their visitor's visa application.