usually you need 3 months maximum to have the stump ready for prosthesis. you get the stump ready by wrapping. in developed countries they also use some sort of fitting (in airbag prosthesis) which also help to shape the stump and improve the patient balance, walking...
The paper entitled "When to biomechanically examine a lower-limb amputee: A systematic review of accommodation times" may conduct you to a direct way. But not sure!
You can have a temporary one after the stump has healed, but you should be aware that the volume of the stump will change during a year, more or less, so you will have to keep doing adjustments to the socket until the volume stabilizes and you can get a more definitive socket.
The recommendation is 6 months after the amputation. However it is different the process for obtaining a prosthetic device comparing high-income countries versus in low-income countries since the health systems is flawly a person could wait years before receiving a prosthesis