A printed or electronic document that proves the customer has booked and paid for a tour or activity. Vouchers are typically not issued until payment has been received for a booking. They generally contain important information about the tour or activity being booked including the name and time of the tour, the guests booked on the tour, pick-up or meeting information, cancellation details, and contact information for the tour operator.
Unlike tickets, which are issued on an individual basis, vouchers are issued for a group. For example, a family of three booking a tour on a given day will receive one voucher with the names of all guests on a single voucher. Vouchers are generally not transferable and cannot be resold, although this policy may differ from operator to operator. Most tour operators will require customers to bring their printed or electronic voucher with them when they show up for their scheduled tour. The tour operator may or may not scan the voucher in order to check-in the group.
More information about vouchers: https://www.rezgo.com/support-article/give-customer-check-voucher