On my Windows 10 version of mSecure 5, I can enter a new record as type "Unassigned". This is handy, since I occasionally use the Unassigned type for free form records where my data doesn't match any of the existing types, and usually they one-offs so there's no point in creating a custom type. However, my Android copy of mSecure 5, V18.104.22.1687, does not allow creation of new records with Unassigned as the type. That's a pain in the neck if I don't have my Windows computer handy.
The "Unassigned" type is a legacy type for the previous version. It was only used because mSecure 4 and below started with users creating an unassigned record type before being able to select a different type. If you want to use this type, rename the record type in mSecure 5 on Windows and it'll be available to you on Android. You could also just create a different record type with the kinds of fields you need for your "free form" info.
Thanks for the explanation, Eden. Something else to keep track of when (if) I ever get around to actually using V5. At present, I'm using V4 and just playing with V5 because I very strongly prefer the V4 interface. Especially on mobile devices.