Ralts evolves into Kirlia starting at level 20. After evolving into Kirlia, it can then evolve into Gardevoir at level 30; alternatively, if Kirlia is male, it can evolve into Gallade when exposed to a Dawn Stone. Thus, the primary evolution level for Ralts itself is level 20. This evolution applies across various Pokémon games including recent ones like Pokémon Scarlet and Violet. In summary:

• Ralts evolves into Kirlia at level 20.
• Kirlia evolves into Gardevoir at level 30.
• Male Kirlia can evolve into Gallade using a Dawn Stone.

This information is consistent across multiple game generations and sources.