É condicional, entre Informações gerais sobre vistos turcos , somente necessário quando uma pessoa ou empresa na Turquia fez um convite ( maior ênfase minha ).
Tourist Visa
If an invitation letter is submitted for a Touristic Visa application, it must include the inviting person's TR Identity Number, clear identity, the list of invitees, permanent address, contact number, length and purpose of stay and the affinity with the applicant must be stated in the letter. If the inviting side is an organization or a company, tax registration certificate of the organization will be required. In the invitation letter it is also required for the inviting person/authority to pledge for covering victuals and accommodation expenses and for taking their own responsibility. The applicant is required to have sufficient and/or regular remunerations.