Hi Alex,
Basically this cannot be done normally in Windows.
When you install software, it is the install software is programmed by the software developer, and on some installers, you would be given the opportunity to 'Install Just For Me', and that would install the software so it is only available on your account.
if the software developer does not provide that option in the installer, then all user accounts on the PC will have access to the software.
This is not caused by a Windows setting and so it cannot be changed because that is the way the software developer has set their software up.
What edition (Home, Pro...etc) of Windows is installed on your PC?
If you do not have the home edition, then you may be able to clock the other user from accessing apps using Group Policy.
There isa tutorial on this link, if you have the Group Policy Editor:
https://www.technipages.com/prevent-users-from-...
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