While it's always best practice to use a headset in a video call, also we have some pretty advanced wizardry under the bonnet to deal with feedback and echo suppression.

If you are still hearing yourself back when you speak, this isn’t an issue at your end, it's someone else in the call who is not following best practice and has their volume too high. To find them, mute each attendee in turn until the echo goes, then ask them to use a headset or turn down the speakers at their end.