When you share browser tab, your mouse cursor is shown as a green disc to the viewer.
If your viewers are not seeing your mouse cursor when you share full screen or application window, then you likely have a version of Google Chrome that is between version 51 and 54. You can check your version by typing chrome://version into a new Chrome browser window.
Starting with version 55, which is the current stable version, meaning that all users should automatically receive it very soon if they haven't already, the mouse cursor is again shown when sharing full screen or application window, as is the intended behavior.
If you're stuck on an older version of Chrome, or if you wish to show your mouse cursor more prominently than just showing the cursor itself, we have found free software that you can download for this purpose.
If you are on a Mac, the free program Mouse Locator works well. Install it, then press control+Space to activate it at any time, and while it's active your viewer will see where you're pointing. Download it here.
On Windows, the free program Cursor Attention achieves a similar purpose. The download page is here.
If you have pointers to other programs that help highlight your mouse cursor, please share them in the comments below!