To activate the credit card tokenization, just follow the next steps:

  1. Access the [Settings > General Settings > Accounting] menu;
  2. Find the [Credit Cards Tokenization] section;
  3. Mark [Yes] in the screen option;
  4. Choose the payment channels that will have the feature activated;
  5. Save the changes made at the upper right side of the screen.

The [Payment channels with tokenization] field refers only to cards imported in OTA reservations and you can only choose one. 
Remember that, for OTA reservations, the cards will be tokenized when the reservations are imported and not after the transaction has been validated, so determining the channel is important for correct operation.

Now that you know how to activate the tokenization on your, how about checking other details?