What is an overview of Christian beliefs on the essential features and functions of an Apostle?

The following are examples of (possible) essential features and functions of an Apostle I've heard from different sources. An authentic Apostle ... 1. Had to be called supernaturally by God Himself in an unmistakable way (canonical example: Paul in Acts 9). 2. Had to have eyewitnessed Jesus Christ in physical form after His resurrection (aka a *Christophany*). 3. Must have a ministry accompanied by signs, wonders and mighty deeds. 4. Must be a church planter (see [Church planting](https://en.wikipedia.org/wiki/Church_planting)) . 5. Must be an effective preacher of the gospel and soul winner in unreached areas. 6. Must have a position of leadership in the church. 7. Must be author of (or should be able to produce at least) inspired and canonizable writings (i.e. we should be able append their writings to the Bible). **Note**: These are just examples off the top of my head, feel free to consider other requirements people have historically proposed if I forgot any. **Questions**: - What is an overview of how different Christian denominations define the essential features and functions of an authentic Apostle? - Would these different definitions of Apostle allow for the existence of authentic Apostles in modern times? ____ Related and thought-provoking question (and answers): https://christianity.stackexchange.com/q/90502/50422