How to encrypt a Mac storage device

Apple allows encrypted drives in two varieties.

Full-disk encryption (FDE) is a low-effort way to ensure that if someone were to get ahold of one of your drives while unmounted or a Mac while powered down, the contents on the drive would be unusable to them without knowing a password or other encryption information. Apple offers two distinct ways of encrypting volumes on a drive, and it's important to know the difference between them and the current limitation on drives connected to M1-based Apple Silicon Macs.