How to get and pass a field value from one Kintone App to another?

Hello @Jayron_Rosel

I assume you are using Company Name as a key to distinguish which record of getting data from. It depends on your situation, but this is an example script that could get and pass a field value from one app to another when a button is pressed.

(function() {
  "use strict";

  var AppId = *App ID you are retrieving data from*;

  kintone.events.on(['app.record.edit.show', 'app.record.index.edit.show'], function(event) {
    // Placing a button on a space field
    var btn = document.createElement('button');
    btn.id = 'my_space_field_button';
    btn.innerHTML = 'Space Button';
    btn.onclick = function () {
      kintone.api(
        kintone.api.url('/k/v1/record', true),
        'GET', {
          app: AppId,
          id: event.record['CompanyName'].value
        },
        function(resp) {
          var record = kintone.app.record.get();
          record['Street_Address'].value = resp.record['street_address'].value;
          kintone.app.record.set(record);
        }
      );
    }
    kintone.app.record.getSpaceElement('my_space_field').appendChild(btn);
  });
})();

Please refer to the Ref. for more examples.
For your information, it depends on your situation, but you can use a lookup field to copy data from another app.

Ref.: