How to create partition without formatting drive?

You can use Gparted (available in the Ubuntu Software Centre) to resize the 2TB down in 200GB and format those 200GB as FAT.

That process does not require you to format the previous NTFS partition, but its always a risk. There is no 100% safe process for that and a backup of your data is always the most responsible thing to do.

Instructions on how to install and use Gparted are here: How to resize partitions?

Just open the program, locate your hard disk, right click on the partition and select resize/move, give it some room on the right up to the amount you need and create a new partition on the new free space. After you applied the changes you will have 2 partitions on your disk: the old one containing your data, and a new formatted 200GB FAT32 partition.

FWIW, it's a pretty low risk - in many years of partitioning drives, I have never lost data when 'using as directed' (eg, don't cancel the operation part way through because it's slow). So, if you use GParted, and don't cancel in the middle or have a power outage, you're 99.9% likely to be fine. But, as Bruno says, there is always some risk. If your data is really that precious, you'll need to back it up; you should do so anyway - hard drives do fail from time to time. (Personally, I'd say mechanical failure of a drive is more likely than failure in partitioning.)
That's the downside of big drives, eh? No fun to lose TB at a time ...