For compatibility and security reasons, Kepler - Multi-Factor Authentification cannot be applied on the mobile application (Android or IOS).
However, it is possible to open it in any mobile browser (view in desktop version).
To secure your Jira instance, we must te disable some plugins in Jira System.
1- Go to Manage apps.
2- In the applications filter, select "System". This has the effect of selecting the Jira system plugins.
3- Search in this list for these two plugins "Jira Mobile" and "Mobile Plugin for Jira Data Center and Server".
4- Deactivate them.
Don't play to deactivate the other plugin !
5- As a result of deactivate this plugins, user will be redirect in web navigator.
Jira Mobile Documentation
You can read more about this topic in the officiel Jira documentation How to enable or disable access to the Jira Data Center and Server mobile app and mobile view in a browser.