When Do Both Spouses Need to sign Listing and Purchase Documents?

​Each person on a deed must execute the Seller Brokerage Agreement
If two or more persons own the property, each name must be listed as a seller on the Seller’s Brokerage Engagement and each owner must sign it. Likewise, each individual buyer whose name will be listed on the title must be listed as a buyer on the purchase agreement, and each should sign it.
 
In Georgia, which is not a community property state, even if a married person owns property individually, the spouse may still need to sign a seller brokerage engagement.  That is because the non-owning spouse may have equitable rights to property held solely in the name of the other spouse. For example, if the wife is the only titleholder of record, the husband may nonetheless have an equitable interest in the property. As a precaution, most closing attorneys will require that the husband sign a quitclaim deed transferring whatever equitable interest the husband may have in the property before the property can be transferred.

Can one spouse sign documents for another spouse?
No, unless there is a Power of Attorney in place. One spouse does not have a power of attorney by virtue of marriage to sign a real estate sales contract for the other spouse. Further, amendments, exhibits and notices must be signed by all sellers.
 
Power of Attorney
If one spouse is going to be unavailable to sign a real estate sales contract, that spouse should execute a power of attorney in favor of the other spouse.
 
Possession as Notice that there may be additional interests in the property.
A person in possession of the property may have rights to the property. In Georgia, if there is a person in possession of property that is not the record title holder, the possession by itself constitutes notice to any prospective purchaser that the person in possession has some title, claim to, or right to be in possession of the property.  Though the possession may only be a leasehold, it could be something else, such as an inherited interest. Buyers must investigate to determine the nature of the person’s interest in the property or the basis for the person to be in possession of the property. The safest course of action in such instances is to obtain written evidence from the person in possession of the property that he is not claiming any interest in the title to the property. For example, a written copy of a one-year lease between the seller and a tenant would establish that the tenant is not claiming title to the property.

Builder Purchase Agreements
Some builders include a provision in their contracts that once the contract is initially signed by both spouses, the signature of one spouse thereafter on any amendment or addendum to the contract will automatically bind the other spouse. This type of provision is particularly helpful when both parties may not be available when the buyers need to make multiple design selections for a new home after signing a contract.
 
An example of this type of provision follows:
 
One Buyer Has Power to Sign for Other Buyer
Each undersigned Buyer, by signing below, does hereby appoint the other Buyer or Buyers herein to act as his or her authorized agent of and power-of-attorney for said Buyer(s) for the purpose of signing any amendments hereto and all other documents contemplated herein, including but not limited to any notices given hereunder, and authorizes the taking of all such actions on behalf of Buyer with respect to this Agreement. All parties agree that if any Buyer signs any document contemplated above, said Buyer shall be signing for himself or herself and for all other buyers, regardless of whether the Buyer indicates that he or she is acting in a representational capacity. This appointment and grant of this power-of-attorney may only be terminated upon written notice to Sell and shall only be effective upon actual receipt of said notice.
 
Reference: Weissman, Seth. The Red Book on Real Estate Contracts in Georgia. BookBaby. Kindle Edition.