In October 2020, the RAND Corporation (a political think-tank) published reports from two seperate studies which (generally) found that
"Social media has made it cheaper and easier for foreign actors to mount increasingly sophisticated attacks on our democracy and our political discourse, Many Americans are immersed in online conversations that have been shaped artificially, and that are giving them a false and distorted picture of the world." - William Marcellino/behavioral scientist at RAND
The latest study used software tools developed by RAND to analyze a very large dataset of 2.2 million tweets from 630,391 unique Twitter accounts collected between Jan. 1 and May 6, 2020. The analysis found that troll and super-connector accounts overwhelmingly cluster in certain Twitter communities engaged in political conversations around the election.
https://phys.org/news/2020-10-efforts-twitter-elections-foreign-based.html
The RAND study found that Russian disinformation IS influencing elections. Due to its popularity, Twitter was the platform of choice, however other platforms were used to spread disinformation as well.