Difference 1: Evangelism is telling others the gospel. Apologetics is defending the truth of the Christian faith.
Difference 2: Apologetics addresses everything from the existence of God to the reliability of the Old and New Testaments. In contrast, evangelism is telling one specific message: the good news about what Jesus Christ has done in order to save sinners.
Difference 3: Another difference between apologetics and evangelism is that apologetics usually requires some level of intellectual sophistication. Apologetics can involve logical arguments, historical debates, philosophical discussions, interpretive disputes, and more. On the other hand, evangelism is simply telling others the message about Jesus Christ. That’s something every Christian—even a brand new Christian—should be able to do.
The link: However, the two can be closely linked. Apologetic conversations can lead to good opportunities to share the gospel. And evangelistic conversations will often lead to apologetics when non-Christians respond with questions or criticisms that require a reasoned response.
Bottom line: So, while Christians shouldn’t let apologetics distract us from sharing the gospel, we should also work to be ready to give an answer to anyone who asks us about the hope that is in us (1 Pet. 3:15).