The video, to be released on 20th March, forms part of this year's Thy Kingdom Come initiative which encourages believers to intercede for their communities and evangelise.
In it, Most Rev Justin Welby says: "We witness to hundreds of things every day. Being a witness isn't unusual, but it's about growing as a witness to Jesus Christ.
"I want to tell people about Jesus because 43 years ago he found me and my life was changed. Through all the really bad and really good, he's never changed. He's always there.
"We exist to show the world that Jesus is the Son of God, that really matters."
The Archbishop appears in the video alongside the Archdeacon of Hackney Ven Liz Adekunle, youth worker and Romance Academy founder Rachel Gardner and the Bishop of Chelmsford Rt Revd Stephen Cottrell.
The group explore why and how believers share their faith, what some of the difficulties are, and how to be a more confident evangelist.
Bishop Stephen says: "Prayer and evangelism belong together. When we pray, we pray that we would see ourselves, others and the world as God sees them, and want to be part of God's work of transformation.
"Evangelism is God's work - he wants the world to be transformed, he wants the world to know Christ. That's our motivation."
Running between Ascension and Pentecost, the Thy Kingdom Come campaign urges Christians to organise events such as worship nights, prayer walks and prayer vigils.