I bought an unlocked new LG Phoenix 2 smartphone (Android) for use with Family Mobile (powered by T-Mobile); the phone was originally sold by AT&T.
It replaces an LG Optimus L70, which I bought used in December 2015 which was "aging out."
The person using the phone made heavy use of the "Memo" app, which allowed me to export/share its memo files individually via Bluetooth to the new phone, where they ended up in "Internal Storage" as files with an ".HTML" suffix.
Here's the annoying part. The new phone, the LG Phoenix 2, does not have an app that can import these files. The Google Play Store does not seem to specify whether the multiple memo/notepad-type apps use ".HTML" files so that I can pick one to download, and finding one via Google search has not worked.