When you hover your mouse over the icon, it says Noise Suppression powered by Krisp.
You can also click the gear icon to the right of your username in the bottom left corner of the app window, then click Voice & Video > Noise Suppression under the “Advanced” header.
You can also go to Settings > Voice > Voice Processing > Noise Suppression.
You can also go to Settings > Voice > Voice Processing > Noise Suppression.