Google Earth Pro Desktop is free and available to download for Windows, macOS and Linux systems. Google Earth for Web is a browser-based version and Google Earth on mobile is an app.
Although the browser-based version has a certain ease of use (since it does not have to be installed as a desktop application), there are some limitations to Earth for Web that do not exist with the Google Earth Pro desktop version.
Google Earth provides search capabilities and the ability to pan, zoom, rotate, and tilt the view of the Earth. It also offers tools for creating new data layers. However, it's not a Geographic Information System (GIS) with the extensive analytical capabilities of ArcGIS or MapInfo, but is much easier to use than those software packages.
Additional Google Earth applications include:
Here are a few suggested resources on how to get started with Google Earth and Google Maps: