While in a Call or Meeting, Microsoft Teams gives you the option to share your Screen or a Window with the other participants.
To do That Click on the Share Button at the bottom of your screen as illustrated in the image bellow.
Once Done, you get the option of sharing your Desktop or any Window you have open. When you click on one of them, every participant should be able to see what you selected.
For example If you chose the Calendar Window, every participant would see your Calendar, and only your Calendar.
Note: It is recommended that only a Window should be shared.