WordPress + Advanced Custom Fields Pro: Enable Google Maps API

functions.php

<?php
// Add this code to the themes functions.php

const GOOGLE_MAPS_API_KEY = 'Your Google Maps API Key';

// Ensure Advanced Custom Fields Pro (ACF Pro) is enabled
//
// Check if plugin is enabled without additionally include the plugin manager for is_plugin_active()
// @see https://developer.wordpress.org/reference/functions/is_plugin_active/#comment-2427
if ( in_array( 'advanced-custom-fields-pro/acf.php', apply_filters( 'active_plugins', get_option( 'active_plugins' ) ) ) ) {
	function my_acf_init() {
		// Set Google Maps API Key
		// @see https://www.advancedcustomfields.com/resources/google-map/
		acf_update_setting( 'google_api_key', GOOGLE_MAPS_API_KEY );
	}
	add_action( 'acf/init', 'my_acf_init' );
}