Search for information on "deep linking", "universal links", custom URLs, and "URL schemes".
Here's an SO question and answers related to the subject: url - iOS deep linking
Also, see the developer documentation "About Apple URL Schemes"
Or, Handling Universal Links
And, Allowing Apps and Websites to Link to Your Content
Another: Defining a Custom URL Scheme for Your App
I will try to update this answer with some examples in a bit, but I wanted to give you something to consider while I find them... (links accessed as of 16 Dec 2019)
Update: from the custom URL scheme article, first, you would create your own URL for clients to use when calling your app. Example:
myphotoapp:albumname?name=”albumname”
myphotoapp:albumname?index=1
Next, you would "register" your URL scheme in the "info" tab of your project's settings in Xcode, under the URL Types section. Here, you're relating your app to the URL scheme (eg, "myphotoapp").
Then, you would handle the incoming URL actions. Quote:
The system delivers the URL to your app by calling your app delegate’s application(_:open:options:)
method. Add code to the method to parse the contents of the URL and take appropriate actions.
And, finally, check out the Always-Updated List of iOS App URL Scheme Names, again, last accessed 16 Dec 2019. Examples from that site are Apple-created deep links that include:
- make a phone call from your app:
contact = tel://TheirPhoneNumber
contact = telprompt://TheirPhoneNumber
Open = mobilenotes://
Update 2: SO help for finding URL schemes of other apps: iOS - Find the URL scheme of an app on my iPhone - might work for iPadOS, too... Suggestions include using an app called "Iconical", using the device console and Springboard
info, and more...