Kattia is a web app that works in your phone's browser. There is no native iOS or Android app, so you use the same website address you use on a laptop.
What the phone layout looks like
On a phone, a tab bar at the bottom replaces the sidebar:
Pipeline shows your applications as a list.
Calendar shows interview and follow-up dates.
Library holds your resumes, cover letters, stories, interview notes and application feedback.
More links to Flow, Analytics, Inbox sync, Contact support, Settings and Send feedback.
Select the plus button at the top of the screen to add an application. Select the search button to find an application or jump to a page.
What differs from a laptop
The board with draggable stage columns is not available on a phone. You see the Pipeline as a list instead. To move applications to another stage:
Above the list, select the Select button.
Tick the applications you want to move.
Select Move to… in the bar at the bottom of the screen, then choose a stage.
Recommendation
Use your phone for quick checks, follow-ups and adding a role you have just seen. For a full review of your pipeline, use a laptop or desktop.