Open Trello links in the iOS App
Trello Links such as a card or board links (trello.com/c/.... and trello.com/b/....) can be opened in the Trello iOS app if certain criteria is met. Some apps hardcode for the links to open in a browser, so they will not open in the Trello app.
Here are steps that you can try to configure iOS apps (and other apps that cooperate and use the setting) to open links directly in the Trello app rather than the browser installed on the iOS device:
Copy a Trello link to the clipboard of the iOS device. You can use the Share button on a card or board in the Trello iOS app. Click share and select "Copy".
Open the native iOS Notes app that is included with the iOS devices and create a new note.
Paste the Trello link into the note. Then tap and hold on the link until the preview and menu appears and select "Open in Trello"