To initiate screen sharing on a Mac, start by granting permission for screen sharing in your system preferences. Here's how:
Click on the Apple Menu in the top-left corner of your screen and select "System Preferences."
In the System Preferences window, locate and click on "Security & Privacy."
Once you're in the Security & Privacy settings, go to the "Screen Recording" tab.
In the "Screen Recording" settings, you'll see a list of apps and browsers. Toggle the switch next to the applications you want to grant permission to record the contents of your screen. Ensure that the toggle next to your web browsers such as Google Chrome and Safari are enabled.
After doing this, close and reopen your web browser.
Rejoin the session you intended to share your screen with by reopening the link session link in your browser.
If you're using the Safari browser and don't see it on the list, click the '+' icon at the bottom of the list. This will allow you to add Safari to the list and enable screen recording for it.
Once you've selected all the necessary apps and browsers, click "Quit Now" to save your preferences.
Note that updating your system preferences may require you to restart your computer for the changes to take effect.