I have questions regarding software development process,Let's assume we have three teams Business analysts Implementation team Quality assurance teamI think that Business analysts inputs is BRD (Business requirements)  from the client, My question is regarding the implementation team  input (the engineers who actually code the software)What is the input for the implementation team?What documentation for new requirement?  is if FSD? Functional specification?  What documentation for a change request (client is requesting a system behavior modification )What documentation for bug fixes?Is there a document template or a methodology to follow?Does Agile cover this topic? 
implementation team - Inputs and outputs
engineering