The preferences screen of the Draft module are found in the Preferences window (Menu Edit -> Preferences).
It has General settings, where you can specify the color of the snap symbols, the default width and color for new objects. By checking the "Save current color and linewidth across sessions" checkbox, any change you make on the draft command bar will be saved here, so you will start your next FreeCAD session with the color and width you were using on quit.
The DXF settings configure how DXF files must be imported.
The SVG settings configure how SVG files must be imported.
The OCA settings configure how OCA files must be imported.