In the MCU(Marvel Cinematic Universe) no date is given to when he recieves the suit. The movie that he got the suit in is Ant-Man, and that movie aired in the US on June 29, 2015.

Ant-Man's suit allows for the user, who happens to be Scott Lang, to grow and shrink in size.

Ant-Man's antagonist for the first movie was Yellowjacket for creating a suit that has the same abilities as the Ant-Man suit, but this time an evil guy is at the controls. In his second movie the antagonist was Ghost. They fought ghost for stealing a piece of the machine they were trying to make.

Ant-Man has appeared on screen in 3 movies so far, and he will be in a 4th by next April. The 3 movies are Ant-Man, Captain America:Civil War, and Ant-Man and the Wasp. The 4th movie is Avengers End Game.

Ant-Man started his story by having a wife and daughter then getting arrested for burglarizing. After serving his sentence his friend tells him about a house with a ton of money in it that he can break into. He originally says no, but in a need to pay his child support bills he decides to break into the house. He only finds the Ant-Man suit, and the owner being impressed gives it to him. In exchange for the suit he helps the owner take down Yellowjacket because he recreated a suit like the Ant-Man suit to use for evil. Later the Falcon asks for his help involving Captain America. For helping Captain America break the law, he gets arrested again. He goes under house-arrest, but since he didn't make the suit the owner gets in trouble as well. He goes into hiding while trying to build a machine that lets him travel to the quantum realm. Ghost steals the last thing he needs, so Ant-Man teams up with the Wasp to take it back. They get it back and decide to help Ghost because she only took it to save her life. In the end credits of Ant-Man and the Wasp, Ant-Man is in the quantum realm while the rest of his team gets disintegrated which leaves him trapped their for now.