The final production stage of the video production is the converting the working file into the final video. This is called the rendering process.
This process is 'really long' and how long it takes depends on the movie length, the processor in your computer and the frame size. As a really rough guide in Premiere, 5 minutes of video at 1080px 'could take three hours'.
This is where a file is converted from a software program working file into a final movie MPEG4, which can then be saved and played on any device that accepts MPEG4.
This file cannot be edited. It is the final cut.
If (any editing) is needed, then it's back to the software and go through the editing process, then rendering all over again.