The U.S. Department of the Treasury's Office of Foreign Assets Control (OFAC) has added several individuals and entities to its Specially Designated Nationals and Blocked Persons List because they met certain legal criteria. As a result, all their property and any interests they have within the U.S. are blocked, and U.S. citizens are prohibited from doing business with them. These sanctions are mainly related to their activities in the financial and technology sectors of the Russian Federation economy. This action was taken under the authority of Executive Order 14024.
Simple Explanation
The U.S. Treasury has put some people and companies from Russia on a special list because they broke certain rules, so now Americans can't do business with them. This is to stop them from using their money and things they own in America.