Your original post said nothing about having purchased Office 2016 - only Office 2019.
You can download Office 2016 via:
Download and install or reinstall Office 2016 or Office 2013 - Microsoft Office
Unless you have previously registered an installation of Office 2016 Home & Student, though, you won't be able to (re)download it from there. Office 2016 is also no longer downloadable from any third-party sites (unless you want to risk a cracked copy), so you'll need to go to
Microsoft 365 instead.