I need help translating 100 words of official letter to Italian. What would be the best approach?

try google translate: https://translate.google.com/?ie=UTF...n&client=tw-ob

Freelancer, UpWork and Elance are all websites that are forums (fora) for people able to do odd jobs, such as translation, online, for pay.

If all you need is the gist of the letter, Google is fine, but if you need a properly written result, I suggest you outsource it online.

If this is an official document you are submitting to a governmental entity in Italy I think you will find it has to be translated by an official translator and that the document would need to be notarized as well.

I would check before using something as chancy as Google translate.

They don't have notaries in Italy; the title "notaio" refers to a different profession. Official documents do need to be translated by authorized translators. If you're not in Italy, ask at your nearest Italian consulate. Then, at least in Italy, they need to get a special stamp at a courthouse. Outside of Italy, I'm sure the consulate offers the same service.

I had to have documents officially translated when applying for Italian citizenship. It was a slow process, and expensive. The translation was not at all well done; I could have translated the documents better myself. But it has the stamp, and that's all I needed.

I've used Emma
https://www.sites.google.com/site/emmatraduzioni/

she is a legal translator and did a fine job for me

I found her through
guidatraduzioni.it

but she is good value and sensible.

As Bvlenci says, the critical issue is not the quality but the stamp (the stamp makes it perfect ;-) )