Android phones have an in-built feature known as Adoptable Storage, which enables users to add an extra layer of storage space for music, pictures, videos, files, and so on.

Starting with Android Marshmallow, Google has built-in an option to use your external storage (micro SD) as your native internal storage. Follow this step-by-step guide in order to do so.

If your Android phone is running out of storage space, many phones will allow you to insert an SD card, which you can set as the phone's primary storage.