Modify the final column mapping

Use the woocommerce_bookings_csv_import_mapped_columns filter after automatic mapping has finished and the importer has resolved the selected headers. This is the right place to make final mapping adjustments that depend on the raw uploaded headers. The snippet below maps My Custom Column to a custom internal field when that header appears in the CSV.

add_filter(
	'woocommerce_bookings_csv_import_mapped_columns',
	function ( array $headers, array $raw_headers ): array {
		if ( in_array( 'My Custom Column', $raw_headers, true ) ) {
			$headers['My Custom Column'] = 'my_custom_field';
		}

		return $headers;
	},
	10,
	2
);