What's the difference between using the microSD card as removable storage and internal storage?
Use your microSD
card as removable storage when there's already content such as your media and other files so that you don't lose this content.
Using the card as removable storage allows you to insert and access the card on any Android
If your microSD card is new or doesn't have content you want to keep, you can set it up as internal storage for your phone. Your phone needs to be running Android 6.0 Marshmallow. This helps to expand the phone storage space since you can migrate apps that you installed and their data to the card. One important reminder, though, is that after setting up the microSD card as internal storage, the card can only be used on the phone where it has been formatted. You won't be able to insert and access the card on other phones.
See the user guide or how-tos to find out how to set up the microSD card as internal storage.