John states there were many things that our Lord Jesus did. He purposely selected the events in his gospel so that people would believe in Christ and turned to Him to be saved. While the other three gospels are narratives of the life of Jesus, the gospel of John is an evangelistic outreach.
Per Overwatcher comment and correction, it should be noted that the things recorded by John comes from the Holy Spirit. Thus, the Holy Spirit through John selected these events as being important events to convince people of the deity of Christ.
A subtle but very important correction.