Custom Fields Settings is located under My Calendar > My Calendar Pro > Custom Fields.

My Calendar supports custom fields to collect event information that isn’t natively supported by My Calendar. Since My Calendar Pro 3.0.0, you can create your custom fields directly in the admin.

Custom field types supported include textemailnumberdatetimeurltelselectcheckboxradiotextarea, and hidden fields.

My Calendar Pro Settings Custom Fields
My Calendar Pro Settings – Custom Fields

Custom fields can also be defined in PHP for more advanced configuration or defined in a JSON file called mc-custom-fields.json, stored in your plugins/my-calendar-custom directory or in your theme directory. An example JSON definition file is in the plugin’s root folder.

All custom fields will be listed in the custom field editor, though PHP and JSON fields can’t be modified in the editor.

Here is an example where two custom fields have been added. Event sub title and Telephone.

My Calendar Pro Settings Custom Fields with two custom fields
My Calendar Pro Settings > Custom Fields with two custom fields.