The "clone" command:

Usage: fossil clone ?OPTIONS? URL FILENAME

Make a clone of a repository specified by URL in the local
file named FILENAME.  

By default, your current login name is used to create the default
admin user. This can be overridden using the -A|--admin-user
parameter.

Options:
   --admin-user|-A USERNAME   Make USERNAME the administrator
   --private                  Also clone private branches 
   --ssl-identity=filename    Use the SSL identity if requested by the server

See also: init