For tel protocol, it's not like this. Since on your device you can have installed more apps able to handle the tel protocol (Phone, WhatsApp, Facetime, Telegram, 3CX and so on), in order to decide which you want to use, iOS allows you to long press the number and it will show you a menu containing all these apps so you can chose. This is due to CallKit integration, app has no particular saying on this. The same is in device's Contacts, where on a contact detail you have to long press the Call button. You can easily try with Notes app, write a number, press Done, it will become underlined and you can long-press it.
P.S As a note, showing this menu is optional for apps themselves, because they may decide their own handling of a detected phone number.
My old post about this when we implemented it:
https://www.3cx.com/community/threads/ios-tel-protocol.53034/#post-217257