Answer: the main purpose of America's Declaration of Independence was to explain to foreign nations why the colonies had chosen to separate themselves from Great Britain.
Explanation : this article gives a bit more info
https://mrnussbaum.com/uploads/activities/rc/deccomp.htm#:~:text=The%20main%20purpose%20of%20America's,separate%20themselves%20from%20Great%20Britain.&text=Congress%20agreed%20and%20began%20plans,members%20to%20draft%20the%20declaration.
