Depends on the term alter. No they mostly didn't alter any votes in the form of ballot tampering.
They could have altered voters perception which was the purpose of the influence campaign they carried out in the name of their favorite candidate.
"First, a Russian entity carried out a social media campaign that favored presidential candidate Donald J. Trump and disparaged presidential candidate Hillary Clinton. Second, a Russian intelligence service conducted computer-intrusion operations against entities, employees, and volunteers working on the Clinton Campaign and then released stolen documents. The investigation also identified numerous links between the Russian government and the Trump Campaign. Although the investigation established that the Russian government perceived it would benefit from a Trump presidency and worked to secure that outcome, and that the Campaign expected it would benefit electorally from information stolen and released through Russian efforts, the investigation did not establish that members of the Trump Campaign conspired or coordinated with the Russian government in its election interference activities."