/**

 * Increment total entry number on each submission

 *

 * @link https://wpforms.com/developers/how-to-increment-a-count-on-each-form-submission

 */

function wpf_dev_update_total_field( $fields, $entry, $form_data ) {

	$my_form_id = 1000; // Form ID to track

    if( $form_data[ 'id' ] != $my_form_id ) {

        return $fields;

    }

    $my_field_id = 15; // Hidden field ID to store count

    $min_digits = 6; //Minimum digits in counter

    // Count the entries and increment the hidden field count by 1 on each submit

    $total_entries = wpforms()->entry->get_entries( array( 'form_id' => $my_form_id ), true );

    $new_total_entries = $total_entries + 1;

    // Add leading zeros and update field

    $fields[ $my_field_id ][ 'value' ] = zeroise($new_total_entries, $min_digits);

    return $fields;

}

add_filter( 'wpforms_process_filter', 'wpf_dev_update_total_field', 10, 3 );