There are 2 approaches: Either have Windows 10 on all PC's, and connect them to LAN and set them (employees' computers) on Child Mode, and make your own computer the parent.
This will ensure direct activity reporting to the extent you want. You will get emails from Microsoft itself I think...
This method was very much criticised as many LGBT and even straight kids faced the wrath of their parents for what they 'searched' on internet.... But you can use it.
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But if you're considering second hand PC's with old Windows (say 8.1 or 7), then your best, most reliable way is to have a closed Guest account system.
1. Set admin Password on USB access, disk access, install restriction, etc. Their work related data will remain in their My Documents only...
2. Set an option on your browser too, in Internet Explorer, I guess, so history won't erase...
For stopping users who want to delete history in Chrome, you can read this:-- Block users from deleting the history in Google Chrome with the Google Apps Admin Console.
(You have to log in Chrome and set a password)
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Another choice is to move to cloud totally using Google's or other services, this will also give you customised emails and webpages:-- Google Chrome Enterprise | Chrome Enterprise | Google Cloud
Decide what suits you best....