labeling drives, related to the file system choice

hi again,
been exploring online (via tutorials, and utube vids), how to best encrypt my drives using LUKS. 
i'm pretty clear on the process now. 

but are a couple of pieces that aren't so clear, yet. 
few points if i may. 

1. where is the best place to find all the documentation around cryptsetup, the commands, various file systems and related flags, and any helpful information for someone learning.


2. i found this good website: 
https://www.linuxfordevices.com/tutorials/linux/encrypting-partitions-with-luks

there are many tutorials of course and videos. but this is the only one i've seen that includes a command to LABEL THE DRIVE. 
which to me is a great feature... so that when i enter my newly encrypted drive > enter passphrase > the drive shows, with this label, instead of 'luks-346987sjlk (big string of characters).. 

so, my query is, in the tutorial in the website, the guy uses FS exfat... and as a result he utilises, the -n flag, followed by 'volume name/label'... 
i've tried this command, using 
mkfs.btrfs
mkfs.ext4 
but neither of these work with this '-n volume_name' ... 

so, i'm seeing that this -n flag corresponds to using mkfs.exfat alone?

here's the full cmd from the website tutorial (in case not looked)

sudo mkfs.exfat /dev/mapper/map_point -n volume_name

so, IS THERE A WAY TO LABEL DRIVES USING OTHER FILESYSTEMS, in particular BTRFS? 
i've not found any docs online showing this, and it's quite specific. 


3. lastly, how important is the mount folder? sometimes i've seen /mnt/ used or /temp/mnt/ and some use mkdir and create a whole new directory... is this part only used for the initial set up of the drive, so it doesn't really matter? as when i plug the drive, my laptop seems to mount it to 'media.... etc.' 

(just wanted to verify this, as i'm no expert and just learning the ways of these fields). 

thanks for reading. 
appreciate any advice to these 3 queries. 

phil



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