Yabia Omer
Yabia Omer is a vast responsa series in which Maran gathers the Rishonim and Acharonim before deciding — teaching not only the ruling but how it is reached.
Yechaveh Da'at
Yechaveh Da'at is more concise, suited to learners who want Maran's conclusions on practical questions.
Learning well
Read each answer in context, separating question, discussion and conclusion. This article is for learning, not a halachic ruling; for practical questions, ask a qualified rabbi.
Sources
Yabia Omer · Yechaveh Daat · Chacham Ovadia Yosef responsa