When you're creating a visit through the Arke app to generate an access code for your visitor, you can enter their phone number manually or select any contact that is registered to your phone's address book.
Please note that you first need to give Arke permission to access this address book. If you haven't done this when asked at initial setup, please follow the instructions in this article for Android devices or this article for Apple devices to approve this access retroactively.
Once this permission is given, some of your contacts or phone numbers might still show as invalid when you select them through the Arke app. This might be because the phone number was saved incorrectly in your address book, or because it is not a mobile number.
As companies like Uber might use premium business land lines instead of mobile phones, their phone numbers can't always be used to send text messages to. Or you might not be given a phone number, like when using delivery services.
Whenever your visitor's phone number is unknown or invalid, you can just use your own phone number to generate an access code. You can then copy and paste the code into the Uber app to share it with the driver or add the code as a note when placing your food order for instance.