How to use Internet Explorer Mode in Edge to view legacy Internet Explorer sites

Some sites are built to work with Internet Explorer and have functionality that isn't supported by modern browsers such as Microsoft Edge. If you need to view one of these sites, you can use Internet Explorer Mode in Microsoft Edge.

To view a website using Internet Explorer mode in Microsoft Edge, use the following steps:

Open Edge and navigate to the website you want to view in Internet Explorer mode.
Click the three dots in the upper right corner of the browser window.
Select Reload in Internet Explorer Mode.

If you don't see this option, check your settings:

Click the three dots in the upper right and go to Settings, then the Default Browser section (or paste this into the address bar and press Enter: edge://settings/defaultBrowser)
Make sure the Allow sites to be reloaded in Internet Explorer mode option is set to Allow.

See this article from Microsoft for more info.