Macros are a convenient way to create complex actions in FreeCAD. You simply record actions as you do them, then save that under a name, and replay them whenever you want. Since macros are in reality a list of python commands, you can also edit them, and create very complex scripts.
How it works
If you enable console output (Menu Edit -> Preferences -> General -> Macros -> Show scripts commands in python console), you will see that in FreeCAD, every action you do, such as pressing a button, outputs a python command. Those commands are what can be recorded in a macro. The main tool for making macros is the macros toolbar: . On it you have 4 buttons: Record, stop recording, edit and play the current macro.
It is very simple to use: Press the record button, you will be asked to give a name to your macro, then perform some actions. When you are done, click the stop recording button, and your actions will be saved. You can now access the macro dialog with the edit button:
There you can manage your macros, delete, edit, duplicate, install or create new ones from scratch. If you edit a macro, it will be opened in an editor window where you can make changes to its code. New macros can be installed using the Addons... button, which links to the AddonManager.
Press the record button, give a name, let's say "cylinder 10x10", then, in the Part Workbench, create a cylinder with radius = 10 and height = 10. Then, press the "stop recording" button. In the edit macros dialog, you can see the python code that has been recorded, and, if you want, make alterations to it. To execute your macro, simply press the execute button on the toolbar while your macro is in the editor. You macro is always saved to disk, so any change you make, or any new macro you create, will always be available next time you start FreeCAD.
Of course it is not practical to load a macro in the editor in order to use it. FreeCAD provides much better ways to use your macro, such as assigning a keyboard shortcut to it or putting an entry in the menu. Once your macro is created, all this can be done via the Tools -> Customize menu:
Customize Toolbars This way you can make your macro become a real tool, just like any standard FreeCAD tool. This, added to the power of python scripting within FreeCAD, makes it possible to easily add your own tools to the interface. Read on to the Scripting page if you want to know more about python scripting...
Creating macros without recording
How to install macros You can also directly copy/paste python code into a macro, without recording GUI action. Simply create a new macro, edit it, and paste your code. You can then save your macro the same way as you save a FreeCAD document. Next time you start FreeCAD, the macro will appear under the "Installed Macros" item of the Macro menu.
Visit the Macros recipes page to pick some useful macros to add to your FreeCAD installation.