In FreeCAD, you can install third-party workbenches and macros called "addons" via the Internet. For example, there are addons such as the following.
addons are developed by a third party separate from the FreeCAD development team and are not necessarily maintained in a stable, but they allow you to use various functions that are not available with the standard features.
Select [Tools]-[Addon manager…] in a menu to show Addon manager. When Addon manager starts, it gets an addons list via the Interneta and show the list.
Show [Workbenches] tab or [Macros] tab, select the addon that you want to install, and then click the
button to start the installation.After installation, according to the displayed instructions, restart FreeCAD to enable the installed addon.
If you wish to uninstall an addon, show the addon manager in the same way, select the addon that you wish to uninstall, and click the
button.If you are accessing the Internet through a proxy server, you may not be able to get the addon list. In this case, click the
button in the upper-right corner of the addon manager to set the proxy in the configuration dialog. After the configuration, close the addon manager and reopen it.If you are still unable to install the add-on after doing the configuration, you can install it manually without the addon manager. Download the addon with a web browser, place it in the "Mod" folder (for workbenches) or "Macro" folder (for macros) of the FreeCAD application folder, and restart FreeCAD to load the addon.
For example, if it is Assembly4, you can download it from "GitHub - Zolko-123/FreeCAD_Assembly4: Assembly 4 workbench for FreeCAD". And you can confirm the FreeCAD application folder by selecting [View]-[Panels]-[Python console] in the menu to display the Python console and executing the following Python code.
On Windows, by default, the FreeCAD application folder is "%APPDATA%\FreeCAD".