I am a SMLLC looking to add a partner to my business.

By "SMLLC" I believe you are referring to a single-member LLC. Essentially, you own an LLC, and you are the only member of that. In Georgia, there is no SMLLC, but there are LLCs owned by a single member. So, for Georgia purposes, you won't change the entity type. You can sell membership interests to another individual in which case you would then share ownership of the LLC with the other person in a manner that you and the other person agree to (50/50. 60/40, whatever).

Typically in these situations, you'll need to ensure that you have a well written operating agreement for the LLC that clearly sets forth how the company will be managed (will you continue to manage it solely? will the other person have a managerial role? who ultimately has decision making authority if you don't agree, or how will decisions be made?). You'll also need to address issues such as distribution of the profits, salaries, etc. The time to get that done is at the start of your business relationship with this other person. If you wait until a problem arises, it will then be much harder, if possible at all, to agree on what to do.

Also, you should consider a Buy/Sell agreement as well, that will specify what happens to the membership interests in the LLC. Suppose you want to get out of the company. Will the other person be required to buy your interest, and, if so, how will you value it? Can you sell it to other people? What happens to your interest if you die? Will life insurance policies be required to provide for the purchase costs of your interest by the other person, etc.?

There are a lot of issues involved in being in business with another person. You should certainly consult a lawyer in your area who works with small businesses, and focuses on ensuring that you do what you can to prevent costly disputes between the owners down the road. That attorney can assist you with the needed documents for your business. And, consult your CPA for financial and tax implications of any possible change you are considering.

This answer is for general informational purposes only, and it not legal advice specific to your situation.