Because this is a generic tablet, official support is rare. Try the retailer where you bought it (Amazon, AliExpress, eBay). Some sellers offer hidden download links if you message them directly.
Typically ranges from Android 5.1 to 9.0 (though many budget tablets spoof higher versions). kt107 tablet firmware
The standard software used for flashing "Scatter-based" firmware. How to Flash KT107 Tablet Firmware Because this is a generic tablet, official support is rare