Learn Farsi: من راننده‌ام.

The word for driver is راننده (rānande), which ends in a silent letter making an "e" sound. When we attach the "I am" ending (ـَم) to a word ending in this vowel sound, Farsi spelling requires an ا (alef) to connect them. It is written as راننده‌ام and pronounced "rānande-am".

Where is the word for "a" in this sentence?

Farsi doesn't use a word for "a" or "an" when stating someone's profession. While in English you say "I am a driver", Farsi simply says "I driver am" (من راننده‌ام).

Do I have to include من (man) at the beginning?

No, you don't! Because the ending ـَم (-am) already tells us the subject is "I", the pronoun من (man) is optional. You can just say راننده‌ام to mean "I am a driver". Including من just adds a bit of emphasis.

Why is the "am" part attached to the end of "driver"?

In Farsi, the present tense forms of "to be" (like am, is, are) are often "enclitics". This means they are short endings that attach directly to the end of the noun or adjective they describe, rather than standing alone as separate words.