This plug-ins enables you to use the native WordPress search functionality to look through your custom fields as well. Plain simple approach, select the custom fields you want to make able to search and it will be searched. ACF Search is plain simple and we developed it according to the K.I.S.S. standard.
You can download the plugin from the WordPress repository. Search for “ACF Search” or follow this link: https://wordpress.org/plugins/acf-search/