Marvel's Iron Man and Captain America: Heroes United is an animated film created by Marvel Animation. The animated movie digitally debuted back in 2014 on Digital HD, On-Demand, and Disney Movies Anywhere. It's an hour and eleven minutes long. You can check out the official trailer below.
The voice cast includes Adrian Pasdar and Roger Craig Smith as Tony Stark A.K.A. Iron Man and Steve Rogers A.K.A. Captain America respectively.
The latter voice actor is best known for such iconic roles as Ezio Auditore from the Assassin's Creed video game series, and Chris Redfield from the Resident Evil video game series but mainly for playing Sonic the Hedgehog in the video game series of the same name but also animated series Sonic Boom.
Marvel's Iron Man and Captain America: Heroes United sees the two titular Avengers battle to prevent the Red Skull and Taskmaster from unleashing a Hydra army on the world. Well, if that piques your interest; Marvel's Iron Man and Captain America: Heroes United is now available to stream on Disney+. Here's a link to the animated movie's Disney+ page.
Similar animated movie, being under the same banner; Marvel's Iron Man and Hulk: Heroes United, also just over an hour long, is available to watch on Disney's streaming service. Here's a link to that animated movie's Disney+ page.