Make Single Field Required

/**

 * Make a single field required.

 *

 * For an example showing how to make multiple fields required, see:

 *

 * @see https://github.com/Charitable/library/blob/master/donation-form/make-donor-address-required.php

 *

 * As of Charitable 1.6 the approach below is the recommended way of achieving this.

 * If you are using an older version of Charitable, see the legacy version below:

 *

 * @see https://github.com/Charitable/library/blob/master/donation-form/legacy/make-donor-address-required.php

 *

 * @return void

 */

add_action(

	'init',

	function() {

		$fields = charitable()->donation_fields();

		/**

		 * Get the field using the field's key. Default options available:

		 *

		 * first_name

		 * last_name

		 * email

		 * address

		 * address_2

		 * city

		 * state

		 * postcode

		 * country

		 * phone

		 * anonymous_donation - If using Anonymous Donations.

		 * donor_comment - If using Donor Comments.

		 */

		$fields->get_field( 'address' )->set( 'donation_form', 'required', true );

	}

);