The HomeScout by Vida app may be found by going to the Apple App Store or Google Play Store and searching for "Vida by HomeScout".
You may also send your client the following URLs:
Apple App Store - https://apps.apple.com/sn/app/vida-by-homescout/id1635630986
Google Play Store - https://play.google.com/store/apps/details?id=com.homescout.locker