With this option type, customers will be able to input free text. It can be used for notes, special requirements, and so on.
To create a free text additional option for your tour:
1. Go to Settings>Tours/activities
2. Click on the specific tour/activity and go to the Options tab
3. Click on the New option button to create a new field
4. Choose the Type [1] of option you want to create from the scroll down list.
5. Input the Title [2] of the option and its Description [3] (optional).
6. Set if an input is required by customers - if the Required [4] checkbox is ticked, customers must input some text when making a booking and they won't be able to proceed with the booking unless they input some text.
7. Set the size of the box - the standard free text box allows customers to input text in one line.
Standard box
Check the Multi-line [5] checkbox if you want a bigger box so that customers can input longer text. 
Multi-line box
8. Choose Permissions [6] by checking the boxes next to
-
This option is enabled for new bookings
-
Customers can see this option
-
Customers can edit this option