QGIS is an Open-Source (free to use) desktop GIS that can handle the needs of most Geospatial projects. In addition to the built-in functionality of QGIS, there are hundreds of so-called plugins that can extend the functionality of QGIS.
Installing QGIS.
Installing QGIS is relatively easy just go to https://www.qgis.org/download/. The website normally determines the OS you are using and gives you the option to download a Long-term version or the latest for your OS. I recommend using the latest.
Mac users After downloading QGIS, open the DMG file. Drag and drop the QGIS application into the Applications folder. The first launch attempt may fail due to Apple’s security framework.
For macOS Sonoma (14) and earlier: To enable QGIS, command-click on its icon in your Applications folder and select Open in the context menu. A confirmation dialog will display where you need to click the Open button again. This only has to be done once.
For macOS Sequoia (15) and newer: To enable QGIS, command-click its icon in your Applications folder and select Open from the context menu. A warning dialog will appear; click the Done button. Next, navigate to System Settings > Privacy & Security and scroll to the Security section. You should see a message stating that “QGIS” was blocked to protect your Mac. Click Open Anyway. A confirmation dialog will appear; click Open Anyway again. This only has to be done once.
Windows users who know they want to use QGIS for more than just some months I recommend using the OSGeo4W installer since it is easier to update QGIS later.
Costimising QGIS
QGIS has a lot of options to customise how it looks and feels. It can, therefore, sometimes be difficult to follow the documentation and QGIS demos| There are two primary customisations you will need to master in order to make your QGIS look like the one someone else is using or in time look how you want it to look, and that is Changing the UI language
Extending QGIS
Plugins are a powerful feature in QGIS that allow you to extend the functionality of the software. Most plugins are available from the official QGIS Plugin Repository—the “app store” for QGIS. Read about installing and managing plugins in the note Managing QGIS plugins