Travellers must apply online for authorisation under the Electronic System for Travel Authorisation (ESTA). A fee does apply, as of summer 2023, the cost is $21 per person.
Apply online - ESTA link
Be very careful and be sure to use this link to the genuine ESTA site. There are many websites out there that will charge exorbitant fees for the service, it is not necessary and should cost no more than the current ESTA charge.
*See note below if you have been to Cuba since 2021.
Overseas nationals arriving into Canada by air require an eTA which as of summer 2023 costs CAD$7 per person.
In addition to ESTA/eTA there are additional requirements which come under the headings of Advance Passenger Information System (APIS) and Secure Flight Passenger Data (SFPD). You will be advised by your Bon Voyage travel consultant how to complete this information.
For the most up-to-date information click here US Homeland Security
Your specific passport and visa requirements are your responsibility and you should confirm your travel eligibility with the relevant authorities.