Start here. This is the direct spoken answer to practice first.
Overview
Both attacks manipulate model behavior, but they target different control assumptions and create different application risks.
Prompt injection tries to make untrusted input override the application's intended instructions or misuse connected data and tools. A jailbreak is usually aimed at bypassing the model's safety behavior so it produces content the model would normally refuse. They can overlap, but prompt injection becomes an application security issue when model influence reaches sensitive context, decisions, or actions.