If I have a new M1 mac and create a Windows guest VM, can I give a copy to my colleague who has an old x86 mac and she can also run it?
(I think I found the answer) https://kb.parallels.com/en/114118 "Note: a virtual machine (VM) created on an Intel-based Mac cannot be started on a Mac computer with M1 chip. A new VM on a Mac with Apple M1 chip must be created (see KB 125375)."
You won't be able to have Windows guest VMs unless you use an ARM version of windows (Currently in Beta). And then no you can't give it to a colleague unless she is also running an M1 mac.
Yes but the VM started on the M1 chip must be Windows 11 ARM edition that is still in customer preview. It will only work on M1 chip macs, it can't be transferred to an intel based Mac. If you rely on running windows VMs, a M1 based Mac isn't the right choice for you.