Why does my android tablet only gives me for Default write disk USB storage and SD card

[Mike too]

Tablet doesn't show as default disk the internal one. Only USB storage and SD card but doesn't write to SD card. Why

 

[Rukbat]

"The default disk" (there's no disk drive in a phone) is called sdcard. The card you put into the card, if you format it as external or portable storage, is called extSdCard. (If it's formatted ad internal or adoptable storage, it doesn't show up, because it's mounted as part of sdcard.)

USB storage is a USB stick or powered external drive you plug into the USB connector. (If you plug in a USB hub, you can plug in up to 6 USB drives - they get labeled UsbDriveA through UsbDriveF.)