Almada, who is 24 years old, spent last season on loan at Lyon, where he played 20 games across all competitions and scored two goals while providing four assists.
The Argentine player has signed a five-year contract with Atletico, which will keep him at the club until 2030.
Almada is known for his versatility and can play in various attacking positions. He is often deployed as an attacking midfielder but can also play on the wings or up front.
This signing marks one of the six permanent transfers that Atletico have made so far during the summer transfer window.