What was the underlying purpose of the Alien and Sedition Acts of 1798?

The background of the Alien and Sedition Acts starts with the undeclared war between the US and France in 1798, also sometimes called the Quasi-War. The United States owed France a financial debt from money borrowed in the American Revolution but refused to pay it once the French Revolution created a major regime change. The US position was that this debt was not owed to the new leaders in France. The Quasi-War was a shipping war on the seas and ended with a treaty in 1800.
Now, to the Alien and Sedition Acts. They were passed by Federalist president John Adams in 1798. They created a series of immigration and citizenship laws. The Federalists were opposed to adhering to old treaties with France and to sympathizing with the French and French immigrants. The Democratic-Republicans opposed the Federalists in these views. Thomas Jefferson was a Democratic-Republican. You can see some primary source materials about the Alien and Sedition Acts at the links below.
https://guides.loc.gov/alien-and-sedition-acts

https://www.ourdocuments.gov/doc.php?flash=false&doc=16