Well, there's a few common ways: As the other member already said, one translation of the word is "alegría". You can also translate that to "felicidad". But in normal speech, you say things like: "I'm really happy today." I would translate this phrase as "Hoy estoy muy contento." or "Hoy me siento muy feliz." You could also say "Hoy estoy muy feliz." When you're talking about "what is happiness", about the big picture, in life, etc. you usually refer to happiness as "felicidad", not "alegría". But if someone tells you that they had a fun time at a reunion, or a birthday party, they usually say: "Estuvo muy alegre!" If someone tells you some good news, for example, that they're going on a nice trip, you can say: "Que alegre!" or you can also say "Que alegría!", and you could also say "Me alegro mucho por tí !" ( I'm so happy for you! ) And if you like to joke a bit, for example, if you were waiting on your paycheck, and it was finally deposited today, in some of our latin countries, you can jokingly say: "Qué felicidad, que felicidad, ya me pagaron!" Hope this helps broaden your ways of expressing happiness in Spanish. Hasta la próxima!

Alegría

Gracias!

Estoy feliz 😁 o Me alegra

Gracias!