Disk Space - Mac Book Pro Disk Utility Info Shows:

Volume capacity : 250,790,436,864
Available space (Purgeable + Free) : 18,254,333,896
Purgeable space : 1,570,408,392
Free space : 16,683,925,504
Used space : 230,210,576,384


Df -h Shows:

Filesystem      Size   Used  Avail Capacity iused               ifree %iused  Mounted on
/dev/disk1s1   234Gi  214Gi   16Gi    94% 2372846 9223372036852402961    0%   /
devfs          189Ki  189Ki    0Bi   100%     653                   0  100%   /dev
/dev/disk1s4   234Gi  3.0Gi   16Gi    17%       3 9223372036854775804    0%   /private/var/vm
map -hosts       0Bi    0Bi    0Bi   100%       0                   0  100%   /net
map auto_home    0Bi    0Bi    0Bi   100%       0                   0  100%   /home


was is /private/var/vm on a 234gb partition? Does that mean this laptop has dual SSD drives?

And lastly, if I start putting files on that partition - will they keep or be erased and the path recreated on a reboot or power off/on??
The /private/var/vm is the macOS virtual memory. It's a special type of file, which is mapped on your Macbook's 234 Gb (formatted capacity) SSD. In short, virtual memory is used when your RAM is full of apps and portions of it is "swapped" to the SSD.
So, your Macbook Pro has only one SSD drive.

If you have Homebrew installed, you can install ncdu with this command in Terminal:

brew install ncdu


and then you can use it in the terminal with:

ncdu 

to see where your Macbook's disk space went.

You can see additional options by pressing ? while running ncdu.