I started out using a Sheaffer cartridge pen calligraphy set. These give a more defined letter and are easy for beginners. But sometimes I would be frustrated because I had trouble getting the ink to flow. I used these pens for several years as I was learning calligraphy. Dip pens give you the best-defined letterforms.
Dip pens consist of a pen holder where a nib can be inserted.
The pen can be dipped into the ink bottle, although it is best to fill the pen with an ink-filled brush or ink dropper. You should then test the ink supply by making a few marks on a scratch piece of paper. Be sure the ink flow is not too fast and not too slow. You can use black or coloured calligraphy ink, available from art supply stores or specialty catalogues, or gouache, which is opaque watercolour that many calligraphers use for coloured writing. There are lots of different manufacturers of these nibs, and you will want to try different kinds till you find the brand that works best for you.