Im not sure if it option is still available to format an sd card to be used as internal storage. If its still an option it is found in the developer options and is just a simple toggle. Developer options are found in settings, it is hidden until activated. To activate developer options go to device info and tap on "build number" 5 times. After that you will have a new option in ur settings menu at the bottom called developer options.
Go to settings>about phone>software information. Then look where it says "build number" and click it 5 times or so. That will activate the developer options, it is a hidden feature you must active first, using the method above. When using as sd card as internal storage make sure you use one that has a U3 speed rating and is a reputable brand. An example would be the SanDisk Extreme Pro series of cards.
Thank you. Developer Options is now visible and it has opened several features and I do not want to touch until I know what they are. I wonder if you could tell me which of these options would let me use my 256 micro SD card as internal memory. Thank you.
There is a toggle setting near the bottom of the list called "force allow apps on external", turn it on.
Then head to a downloaded app that you want to move to the sd card. Click and hold the app until some options come up, such as uninstall, app info. Click on app info, and navigate to "storage", then at the top it will give you the option to change the location from internal storage to the sd card.