How to get ordained in Ga?

Google

Contact whatever agency is going to issue your license. In most states, it's the county, but you could also call the state. In NJ, just for info, it's the town.

I think its just an online course. My friend said her 16 year old daughter took a course online for $10. If you google it there are tons of websites you can choose from. Depends on your preference.

There are lots of places that will do an online ordination. Just put "online ordination" into Google, and you'll get a ton.

The real issue is whether a wedding performed by someone ordained online will be recognized in Georgia. Georgia does not appear to have specific case law, one way or the other (and people in other states have been surprised, sometimes decades after the fact, to discover they weren't legally married). You've got some protection in that Georgia has a law saying that if you believed the officiant was legit, your marriage won't be invalidated if it is later found that s/he wasn't. But if you want 100% certainty, a) you get married at the courthouse the day before, or b) you get someone with a real (not online) ordination to marry you, or at least sign the papers.

I have signed the license after someone else 'officiated' -- maybe you could have a legal officiant do that for you.