In general we recommend to choose Krisp microphone from within web app audio settings. However there are some web apps which don't expose such setting.
For these cases, you can choose Krisp microphone from Chrome settings. When you do this Krisp will be used with all browser-based apps or services, by default.
Copy the following URL in your Chrome address bar:
chrome://settings/content/microphone
And pick Krisp microphone from the exposed list.
Unfortunately you cannot choose Krisp speaker in this way.