Arduino is a developer community, a programming language, an Integrated Development Environment and a series of programmable micro-controllers.
An easy platform to through which one can learn about programmable microcontrollers, supported by a variety of hardware platforms.
The IDE is frequently updated, and it’s well worth keeping your version current. However, make sure that the hardware you are using is supported by the version you are about to install.
It is possible to use an Arduino without using the IDE, for example, Visual Studio Code, combined with the PlatformIO plugin is a popular setup.
Everything you need to know about Arduino including the above links, forums, tutorials and getting started instructions.