Я делал так
HTML
<section class="map" id="map" data-long="<?php echo get_field('b10_map')['lng']; ?>" data-lat="<?php echo get_field('b10_map')['lat']; ?>"></section>
JS
var gmap = document.getElementById('map');
 var latitude = parseFloat(gmap.dataset.lat);
 var longitude = parseFloat(gmap.dataset.long);
 function initMap() {
     var place = {
         lat: latitude, // широта
         lng: longitude // долгота
     };
     var map = new google.maps.Map(
         document.getElementById('map'), {
             zoom: 18,
             center: place
         });
     var marker = new google.maps.Marker({
         position: place,
         map: map
     });
 }
FUNCTIONS.PHP
function my_acf_init() {
	
	acf_update_setting('google_api_key', 'YOUR API KEY');
}
add_action('acf/init', 'my_acf_init');