You can find the freeform pen tool beneath the pen tool in the panel. Select it and you will see a selection of options along the control bar.
Set to shape or path in the top left (pick tool mode). Set a fill as well as stroke and also the stroke options (dashed etc). If the path is selected then you can also enter a value for the height and width for the design so if you want it to be 200px / 200px then enter that in the height and width.
Go to the path operations, the default is new layer so each and every time you create something it will be a new path. Set it to combine and draw the design and if there is already a design selected then the path will be added to that. `You can also select the subtract and it will erase from the current. Set it to subtract first and then create a vector shape and then apply
You can set magnetic on. You can use this to follow around a path as well as use it with images and follow artwork in the image such as if there is a skyscraper or a clearly defined person in the picture, you can use the magnetic feature to create a path around it. Go to the settings panel (little gear) in the middle of the control bar and set to 50 / 10 / 100 and you will get a lot of points. Set it to 50 / 10 / 5 and you will get a lot less points.
Go to the direct selection tool and select all the points and then go to the edit menu and use the define custom shape command and it will be saved to the presets panel for future use via the custom shapes tool. You may find the menu command is greyed out, you need to select all the points or sometimes the command is disabled.