As a rule, unless you are exempt, you are required to have a visa. It must be applied from the relevant Mexican embassy or consulate in the applicant's country of residence.
You can find more information on the website of the Mexican National Migration Institute:
Or in the webpage of Mexican embassy or consulate in your country of residence
In order to apply for an official invitation letter to apply for VISA, first you have to be registered and have booked accommodation.
Then, we will send you an official invitation letter to apply for VISA.