As of my last knowledge update in September 2021, Volaris, a Mexican low-cost airline, typically offered several seat selection options, which may have evolved or changed since then. To select seats on Volaris, follow these general steps:

1. During the Booking Process:

   • When booking your flight on the Volaris website or mobile app, you will often have the option to choose your seat. Depending on the fare type and availability, you may be able to select a seat for free or for an additional fee.

2. Seat Types:

   • Standard Seats: Volaris usually provides standard seats in the main cabin. These seats may vary in terms of legroom and location, and you may be able to select one for free, especially if you book well in advance.
   • XL Seats:  volaris seat selection offers XL seats, which provide extra legroom. These seats are usually available for an additional fee.
   • Preferred Seats: Some airlines offer preferred seats, often located near the front of the aircraft or in exit rows. These seats may offer additional benefits, such as more legroom, and typically come with an extra fee.
   • Upfront Seats: You may have the option to choose upfront seats, which are located closer to the front of the plane for faster boarding and disembarkation. These seats often come with an additional cost.

3. Seat Selection Fees: Be aware that selecting certain seats, such as XL or preferred seats, typically incurs an additional fee. The fee amount can vary depending on factors like the route and the seat's location.

4. Select a Seat Later: If you are unsure about your seat choice during booking, you may also have the option to select or change your seat at a later time, closer to your departure date. However, availability may be limited, and you might not have as many options compared to booking in advance.

5. At the Airport: Alternatively, you can choose your seat during the airport check-in process. However, keep in mind that preferred or extra-legroom seats may have limited availability at that time.

For the most up-to-date information on Volaris' seat selection policies, fees, and options, I recommend visiting their official website or contacting their customer service directly. Airlines can change their policies, fees, and available services over time, so it's essential to verify the current details for your specific flight.