We are all called to have faith. So all of us are called to evangelize, while some are specially gifted for this ministry.
Mark DeverAdvice on evangelism needs to be tailored to individual situations. For instance, I know someone who needs to be encouraged to speak less and work more. That would be a better testimony for him because he has certainly let his work colleagues know about Jesus. It's not that I don't want him to witness about Jesus, but I have a lot of sympathy for his employer. He is paying for work to be done.
Mark DeverIt's fine to deal with people's doubts and explain why they have good reasons to believe in Christ. But until we tell them the good news of Jesus Christ, we haven't done our job. They need a saviour that God has provided them in Christ. Once they know that, we can do as much apologetics as we need to.
Mark Dever