Here is link to Google Camera app: https://play.google.com/store/apps/details?id=com.google.android.GoogleCamera
I use Google Camera app to take photospheres and use the Street View app to manage them after I manually uploaded them by computer. I like the controls of the Google Camera app.
Make sure you let the phone finish processing the photosphere before taking more photos or you run the risk of losing that photosphere.
I copy my photospheres to a dedicated Google Photos album and also back them up to Google Drive and my local SSD. Then I will upload to Google Maps (and any new photospheres will also be uploaded to Mapillary). This process ensures that my photos are backed up and I can safely delete the photo off the phone to save space.
I just started going back through all my old photospheres and started manually uploading them to Mapillary.
I found that there wasn't anything I had to do to my photospheres for Mapillary. I just simply manually upload them.
I got about 100 photospheres and it will take some time to upload them to Mapillary as some are connected with each other.