Activate under DESIGN > Solid > Create > Helical Gear +

Enter gear parameters

Preview if necessary

Click OK

Install:
Double-click the downloaded installer from Autodesk App Store to install the app/plug-in.

Uninstall:
You can unload the add-in without uninstalling it by clicking the "Stop" button when the add-in is selected in the list box on the "Add-Ins" tab of the "Scripts and Add-Ins" dialog.
Unchecking "Run on Startup" causes the add-in not to be loaded in future sessions of Autodesk® Fusion 360™.
- Navigate to the ./ApplicationsPlugins folder and select the app bundle you want to uninstall
- Either drag the app bundle to the Trash or right-click and select “Move to Trash”
- Right-click on the Trash-Can and select “Empty Trash”
- If you prefer keystrokes, you can also just select the app bundle and then hit Command+Delete to move the app to Trash, then empty the Trash and the app will be removed.