Yes, you can do all the partitioning from within the installation from
an ISO disk or flash drive. Gparted is handy for the times you might
want to set up your partitions in advance for more than one version of
Linux or whatever. I'm not sure that Gparted comes with the
installation but it's certainly available in the repositories or you
can go to their website and download an ISO to burn as a standalone
self booting app.