Address Autocomplete attaches itself to your address field once the page has loaded, so the field has to be on the page by then. If it’s in a popup, or hidden until someone picks an option on your form, it isn’t there yet when the plugin looks.
Try the Start delay setting first. It makes the plugin wait a few seconds before it looks, which covers forms that load in a little after the page. Start delay explains where to find it.
If the field only shows up after someone clicks something, a fixed delay won’t always line up, so you can start the plugin yourself with a little JavaScript once the field is visible. Calling wps_aa() attaches Address Autocomplete to any fields that are on the page at that moment.
This example waits for a change on another field, gives the hidden fields half a second to appear, then starts it. Change #element to match your form:
jQuery( '#element' ).on( 'change', function () {
setTimeout( wps_aa, 500 );
} );
For an Elementor popup, start it when the popup opens:
jQuery( document ).on( 'elementor/popup/show', () => {
wps_aa();
} );
Setting up a form inside a popup? The field picker has a Pause button, so you can open the popup on your page, click Resume, then pick the fields inside it.
Premium customers can open a support ticket for help with their form.