The files that make up VMs are put in the same folder in a datastore by default.

They are:

1. VM Configuration File (.vmx) – is a text file, the most critical file for a VM. It will be populated by many settings governing not only what virtual hardware is presented to and seen by the guest OS but also parameters needed to properly work with a particular OS.
2. VM Disk Metafile (.vmdk) and Flat File (-flat.vmdk) – represents the VM hard disks and always come in pairs. The VMDK file contains metadata used by ESX/ESXi, describing the -flat.vmdk file that is the data file that represents the VM hard disk. Whenever we add a hard disk to our VM, we will have a new pair (.vmdk and -flat.vmdk).
3. VM BIOS State File (.nvram) -  is created when the VM is created and represents the BIOS of the VM.
4. VMkernel Swap File (.vswp) – is used by the ESX/ESXi host if it needs to swap the VM out of RAM. This file is always equal in capacity to the amount of RAM configured for a VM unless the VM has a memory reservation. In that case, it will be reduced by the amount of the reservation.
5. VM Log Files (.log) – will grow to 5 MB in capacity before being rotated. 10 generations of log files will be kept before being rotated out and deleted, by default.