Effective April 1st, 2021, all foreign tourists to the state of Quintana Roo (which includes Cancun) must pay a new tourist tax of $224 Mexican pesos (approximately $14 CAD) per person. The tax is required for every traveller 15 years of age and older, and must be paid prior to departure from Quintana Roo.

Hotels are not involved with the collection of this tax. Your clients can pay the tax themselves or you can do it for them via the new VISITAX government website:
Payment can be made either before or during their stay by filling out a quick form on the VISITAX website.  https://www.visitax.gob.mx/sitio/  Tourists travelling together can be included on the same form and processed as one transaction. The form will ask for number of people travelling, names, ages, passport number of each individual, and departure date.
Upon payment, the website will provide you with an individualized receipt for each traveller.
Once your clients have concluded their stay in Quintana Roo, they must show their receipt at the airport prior to boarding. Last minute payments can also be made with cash at Cancun International Airport.