You will hear お and ご attached to the front of many nouns. They add politeness or respect, and a few have fused to their words so firmly that dropping them sounds wrong.
The rough division
お (o-) with native words
Tends to attach to words of Japanese origin. お茶 (ocha, tea), お金 (okane, money), お名前 (onamae, your name).
ご (go-) with Sino-Japanese words
Tends to attach to words built from Chinese-derived readings. ご家族 (gokazoku, your family), ご注文 (gochuumon, your order).
It is a tendency, not a hard wall, and there are exceptions, but it gets you the right prefix most of the time.
Optional versus fixed
For many words the prefix is a politeness choice you can switch on or off. For others it has fossilised into the word itself. ご飯 (gohan, cooked rice or a meal) is almost always said with ご. お茶 is nearly always お茶. Saying plain 飯 (meshi) for rice exists but is rough and masculine.
namae to onamae, your name (polite)
chuumon to gochuumon, your order (polite, as staff say it)
Where it fits
These prefixes are one small piece of the politeness system. The fuller picture, including humble and honorific verbs, is in the keigo guide.
Test one of these examples in the translator and see how it comes out.
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