Tips for Using a microSD Card with Your Fire Tablet
Compatible Fire tablets (5th Generation and higher) support external microSD cards (sold separately) for additional content storage options.
When first inserting a microSD card into a tablet, you can designate it as portable or internal storage. Note that Fire Tablets only support the FAT32 file system.
Portable storage
Best for transferring content such as files, photos, and videos between devices. Some media, such as movies or music, that is copyrighted from apps, may not transfer between devices. However, the content will still occupy space on the card. Kindle books stored on the card will only be accessible on other devices when using the same Amazon account. Forcibly removing a card designated as portable storage may result in data loss. You can safely remove the card by going to Settings, and then selecting Storage.
Internal storage
Best for expanding device storage. This option supports storage of apps and games. Note that some apps may not support card storage. After selecting the internal storage option, the card is formatted and you’ll be asked if you want to move files to the card immediately. If you choose to skip this step, your content will continue to be stored on your tablet and not the card. You can change these options later by going to Settings on your Fire Tablet.