Formatting external sd card as an internal storage
When you format sd card as adoptable storage it will behave like internal storage you can move apps on it. But beware it will be encrypted so it can't be used with other device until you format it to external storage. Apps can be moved from internal storage to adopted storage as much as you want but if you want to format sd card to be used as external storage it is necessary to move apps and media to internal storage or they will be wiped  (because that is what formatting do it erase all data on partition you format).