What I want to be able to do is make my raspberry pi use my 1TB Flash drive as the root file system drive for raspberry pi so I can run everything trough it. I want to do this because my current SD card keeps running out of space. So also is it possible to split the file systems? So the Operating systems on the SD card and everything else on the flash drive?
You can put your filesystem on an external drive, there are instructions to use an external drive to boot your Pi. See https://www.raspberrypi.org/documentation/hardware/raspberrypi/bootmodes/msd.md
Alternatively you can continue to boot from SD Card, and use external mounted storage. See https://www.raspberrypi.org/documentation/configuration/external-storage.md
NOTE all of these use storage accessed via the USB2 interface, which is shared with networking (except WiFi on Pi3), so the throughput is limited; there is NO POINT in using high speed storage, such as a SSD.
Particular care needs to be given to the power supply; while the Pi should be able to power most devices, problems are common.
Another possibility you may consider is to use external networked storage, such as a file server.
One little not as long as its a flash drive you will be good to go (Like this : https://www.sandisk.com/about/media-center/media-resources/product/retail/usb-flash/cruzer-force) but not like this : https://www.wdc.com/products/portable-storage/my-passport-ultra.html For some reason I couldn't get it to work through the hdd but through the flash drive it worked but it was very slow compare to my Samsung 32Gb Micro sd Card