macOS comes with the curl tool bundled with the operating system since many years. If you want to upgrade to the latest version shipped by the curl project, we recommend installing homebrew (a macOS software package manager) and then install the curl package from them:
brew install curl
When you install
curlthe tool with homebrew as described above, it also installs libcurl together with its associated headers.
libcurl is also installed with macOS itself and always present, and if you install the development environment
XCodefrom Apple, you can use libcurl directly without having to install anything extra as the curl include files are bundled there.