This is typically addressed in the Contract to Buy. But many sellers (and seller's agents) prefer to provide all disclosures up front. Agents are able to upload documents to the MLS, such as Seller's Property Disclosure, Square Footage Disclosure, HOA docs, Closing Instructions, etc.
When I'm a Buyer's Agent, I like to have these docs before I write a contract to buy. There might be things in the disclosures that I want more information on, that we can ask for in the contract under "due diligence docs" or additional provisions.
I say it's better to be proactive and have all your disclosure docs ready to go when you list your home, rather than scrambling down the road, after you get a contract.