This is the Holy Grail for almost everyone. I will try and keep this as short as possible.
To understand the draw lets first discuss the slice.
The slice occurs when the club head is on an outside to inside path on the the forward swing. The club face is also open relative to the path the club is traveling on.
So to draw the ball we need to do the opposite.
The draw occurs when the club is on an inside to outside path on the forward swing. The club face is also closed relative to the path the club is traveling on.
To try and help this process along for the draw, you can close your stance slightly, front foot closer to target line than trail foot. This will aid in the club being able to approach the ball more from the inside.
This all sounds relatively easy, however, in my opinion the draw also requires more club face rotation through the impact zone.
You may be able to get on the inside of the ball, but if the face is not rotating properly the ball will just start right and stay right (for a right handed player). There needs to be a certain amount of face rotation (toe of club passing heal of club) through impact.
Because of this there is a lot more timing required to hit a proper draw shot, and why it’s generally a harder shot for most people to hit.