I bought this tablet in 2016 and love using it as it is so reliable,  But, has it reached the end of it's usefullness. I can't add any more apps unless I delete one. Most, if not all apps download to internal storage despite there being a 64GB external storage SD card. I save all of my photos and files on that card but can't get any apps to save on the card. 

Is there a way to increase the internal storage and if so how is it done.