First of all, go to the Product Options Kit app dashboard. Click on the "Option List" top menu button in the app. Here you can see the "Create New Option" button on the right side of this page. Just click on this button, an option form will appear.

This option form has these fields

1. Display Name ( Which name of the field you want to display on your products page. )

2. Unique Name ( Please enter the unique name of custom field option. )

3. Tool tip Text ( Please enter tool tip message. )

4. Help Text ( Please enter help message. )

5. Option Type ( Please select your option type field. )

6. Required ( Check this box to make your field required or not. )

Also, you can manage additional charge to the customers, by selecting "Manage Price" settings.

1. Create Charge

2. Use Variant Price

1. You can add manually charge to your customers for this custom setting field.
2. Also, you can add the price from your variants.

After fill up all settings field, Now click on the "Save" button to create your custom option.