We have a small office and after training reset the laptops. Windows 10 does survive just fine. If you want to make sure your data is irrecoverable you have to decide how deep you must go.

For most two steps will do. 1. Create a new user account, log into that account then remove the old account and files. 2. Make a pass of CCLEANER to wipe empty drive space. https://www.ccleaner.com/docs/ccleaner/using-ccleaner/wiping-free-disk-space and finally a factory reset.

Now if you are truly paranoid you just pull the drive and hammer it. Data is all gone.

Some will use a drive wipe program (DBAN) but then to reload the OS is bit of work. At the office we use the first method for machines to be donated.