Proxmox (Host)

Enable QEMU Guest Agent in VM Options

or in CLI:

qm set VMID --agent 1

Install on Linux

Ubuntu/Debian

apt-get install qemu-guest-agent

RedHat/Centos/Fedora/Rocky

yum install qemu-guest-agent

Start/Enable

systemctl enable qemu-guest-agent
systemctl start qemu-guest-agent

Install on Windows