You can edit the asset fields of an asset on the web and in the mobile app.
To edit an asset on the web, you can either click the 'edit' button on the view asset screen...
...Or view an individual asset and click the edit button.
To edit an asset in the app, go to the view asset screen.
Click or search for the asset you would like to edit.
Press the edit button in the individual asset screen.
Press save when you've completed your edits.
The edits are then logged in the history tab underneath the individual assets.