Hello,
My name is Veejay, I'm an Independent Advisor.
They wont be able to see your other applications while in a meeting just make sure that when you share your screen, do not choose Desktop as it will share your entire screen. Instead, choose only the application you want to share under Window category.
Kindly check on this link for more information:
https://support.microsoft.com/en-us/office/show...
Please let me know if you have any questions or concern.
Thank you