PostScript can make a copy of your fonts and send them along with the instructions for printing your file. This is great when you print to a file. If you make a PostScript file with your fonts embedded in it, then anywhere you send it your fonts will travel with it. Adobe Distiller uses a PostScript version of your file to make your document portable. If you embed your fonts into the PostScript, they will be embedded into the PDF file too.
PostScript instructions are only possible for certain printers, like high-end laserwriters.
Inkjet printers normally cannot read or be used to generate PostScript files. Inkjet printers can't interpret PostScript and so are not PostScript printers. Neither are many less expensive laserwriters, nor printers that use the PCL language. This software, called a 'driver,' can be used to print the PostScript instructions into a file. You can instal a PostScript driver onto your machine without having the printer.