ESXi upgrade via VUM on local datastore

Hi,

Inherited an ESXi which is still on 6.0U1 and will upgrade to 6.7U3 via VUM (It is a supported Gen9 model)

What am trying to understand is where exactly the ESXi has been installed as it has only 1 local datastore (Storage Controller uses RAID).

I believe that ESXi creates its own partition/s, but can these co-exist with VM's?

Just trying to understand the partition structure (datastore is VMFS5) as when I browse through its files I do not see the ESXi partitions.

Also to make sure when I upgrade via VUM that it will only touch the ESXi install and nothing else?

Thanks