Answer:
The Atlantic charter was an agreement signed between American President Franklin D. Roosevelt and British Prime Minister Winston Churchill.
The Yalta conference was a high-level meeting of leaders from the US, Soviet Union and United Kingdom (Franklin Roosevelt, Josef Stalin and Winston Churchill)
The purpose of the Atlantic Charter was to outline the plan for the post-war world and more particularly to address the redistribution of power and influence, which namely, that would be America's role: to safeguard freedom by assisting democratic nations at war with supplies.
In regard to the Yalta conference, its purpose was to strategize the end of the war and discuss what would happen once it was over.