Combination function to let multiple shapes change to one special shape, you can union, subtract, intersect, exclude, divide the shapes.
Union: 
-> 
Subtract: -> 
Intersect: -> 
Exclude: -> 
Divide: -> 
eg. Create a Cloud Logo:
1. Add 3 shapes, 2 different circle and 1 round rectangle, place like this:
2. Select all the 3 shapes, and click union button:
Advanced eg. :