MAVSDK C++ is a library that can be installed and then used in your C++ code.
The latest release can be installed using prebuilt artefacts. If you need the latest state or want to debug the library itself, you need to build it from source.
Ubuntu
If you have an older version already installed remove that first:
sudo apt remove mavsdk
The prebuilt C++ library can be downloaded as a .deb from releases, e.g.:
wget https://github.com/mavlink/MAVSDK/releases/download/v3.0.0/libmavsdk-dev_3.0.0_ubuntu24.04_amd64.deb
sudo dpkg -i libmavsdk-dev_3.0.0_ubuntu24.04_amd64.deb
Install Homebrew and use it to install the library:
brew install mavsdk
For Windows you can download the mavsdk-windows-x64-release.zip file from MAVSDK releases containing the headers and library and extract it locally (see information how to use a locally installed library).
For more detailed instructions or other platforms check out how to build from source.