Check through all the tabs that come up in the dialog on screen. Should you see anything that you don't recognize, or anything that doesn't match up to the programs you know you have installed, or that just seems suspicious in its behavior (excessive disk usage maybe), then a quick web search for the app or process name is usually enough to reveal what you're dealing with.
You should also check for applications and processes that are starting up at the same time as your operating system, as most surveillance tools will need to do this. On Windows, you'll find this list of software under the Start-up tab of Task Manager; on macOS, open System Preferences then select Users & Groups and Login Items. Again, run a web search for any application that you're not sure about.
The macOS Activity Monitor tells you what's going on with your system.
There are some extra permissions stalkerware apps are likely to need on macOS: From System Preferences head to Security & Privacy, and then Privacy. Check the entries for Input Monitoring and Full Disk Access, as spying software will often need these permissions. Windows doesn't have exactly the same setup, but you can see the permissions that apps have (including location, camera access and so on) by choosing Privacy from the Settings menu and scrolling down to App permissions.
As we've said, if your employer is keeping tabs on your working day then the tools should be visible and running with your knowledge. But if you're really worried, a complete system reset for Windows or macOS should clear the majority of hidden monitoring tools, if you suspect one has taken root (just make sure you back up your files first).
How to Check Your Accounts
For someone who wants to invade someone's privacy, it's often easier just to gain access to their online accounts rather than try to get access to their devices. With just about everything accessible on the web, from social media to email, it's far more effective.
With that in mind, as well as checking for unauthorized access to your devices, you should also check for unauthorized access to your accounts. This obviously starts with protecting your usernames and passwords: Make sure they're known only to you, difficult to guess, not used across multiple accounts, and not written down anywhere. Consider using a password manager to keep those passwords strong, randomized, and different for every account you have. On accounts where it's available, turn two-factor authentication on.
