You'll find the option under the “User agent” heading of the “Network conditions” tab. Click those, then press “More tools > network conditions”.
With the developer panel now open, you'll see another three dots in its top-right corner. You can do so under the “More tools > Developer tools” headings, or by press Ctrl + Shift + I. Instead, click the three dots in the top-right of your browser window to open the context menu. Initially, it will show the download for the Media Creation Tool, but don't worry about that just yet. Head to this webpage where you can download Windows 10 Pro, Home, and other editions. Navigate to the Windows 10 download site and open the context menu.As long as they allow you to change your user agent string, it should work.
We'll be using Google Chrome for the purpose of this tutorial, but the general concept should work on any major browser – including Firefox and Edge. This way, Microsoft assumes you can't run its Media Creation Tool and offers you the more widely compatible ISO instead. Obtaining Windows 10's official ISO requires changing your browser's user agent string to one that isn't Windows.