Recebi um tipo semelhante de carta-convite para uma das conferências. Espero que isso ajude você
The Visa Officer, [Country Name] Embassy
Subject: Invitation Letter
Dear Sir/Madame, Please accept this letter as a formal invitation for [Full Name] .that has been invited to attend the [purpose for invitation], held at [location, complete address], [date]
Below are the passport details of [Full Name] Full Name
Position
Organization
Passport No:
Expiry Date
Date of Birth
Nationality
Please note that all expenses during the [purpose] will be covered by [name / organization who is sending the invitation letter].
We, therefore, request that a [visa type] be issued to [full name] to enable him to travel to [Location] to attend [purpose of invitation].
If you require any further clarification or information, please do not hesitate to contact the undersigned.