Put this code in your functions.php file. Then, change the part “field_123abcf” below with the field key of the field you want to change the label
function my_acf_load_field( $field ) {
$field['label'] = "Place : ";
return $field;
}
add_filter('acf/load_field/key=field_123abcf','my_acf_load_field');