Editing.

What is editing?
Editing is the process of condensation, correction, organization and various other modifications in media.
Someone who edits is known as an editor and their roles when editing includes:

• Cutting frames, removing frames that aren't needed.
• Cutting down what may be around 200 hours of footage to just 2.
• Making everything flow smoothly, making sure it looks realistic and natural for the audience.
• Adding music.
• Adding visual effects.
• Including sound effects in scenes.