Dear attendee, here is the template for the invitation letter if required. Please fill out with what you need and send to firstname.lastname@example.org and email@example.com for signature.
You can also find an invitation letter in Spanish here in order to apply for a Visa in Colombia.
This is the link to regulation on Colombian visas where you can find all the requirements to apply. Also, general information about this visa is displayed on the following link: https://www.cancilleria.gov.co/tt_ss/v-participante-evento