Hi Nikita, in addition to spinning a mouse scroll wheel for zooming, there are also these ways which are for compatibility with various other apps:

Alt + Ctrl + Left drag up and down = Zoom
Ctrl + Right drag up and down = Zoom
Alt + Right drag up and down = Zoom

Also there is a "Zoom" button on the bottom viewport toolbar, you can left click and drag up/down on that with no modifier key also. That one was actually made with tablet use in mind. It acts with a kind of continuous motion so only move a small distance when using this one.

- Michael