For the Invitation Letter to be valid, the host should meet certain conditions: they must be a citizen or lawful permanent resident of the country the applicant plans to visit, and a friend, significant other, or relative of the applicant. Additionally, the host should have a registered place to stay that has enough space for the guest. While not every consular office requires an Invitation Letter, submitting one can improve the chances of visa approval. Key details to include are the host’s full name, immigration status, contact information, and the full name and purpose of the trip alongside effective documentation.