I use a few Windows programs that are "installed" like you say. I prefer programs that have a Windows installer though.
My work laptop is managed and wouldn't let me install my own software that isn't managed by IT if they hadn't modified it to let me log as an administrator since, as a software dev, I need to do all kinds of strange things to it.
Manufacturer-signed installer, Microsoft-signed DLLs or executables. Anything else is a virus.
> will they "install" it if there is no installer
Probably not. SysAdmins tend to use remote installation methods like this one to push a software installation to a workstation, so the installation software needs a command line with switches interface to setup for automated silent installs.
https://learn.microsoft.com/en-us/troubleshoot/windows-serve...
It works well and saves a lot of time going around to individual workstations spread across multiple floors.