Every picture tells a story
Many positions in film will require a portfolio of work in order to be hired. A showreel is a short video that compiles the best clips that demonstrate your work. A portfolio is a physical or digital collection of your work.
You may wish to set up a website to showcase yourself, which can host a showreel video, your credits, your bio and some select portfolio assets. Be clear about the contribution you made in the production.
Screenwriters often have sample scripts or other written works to showcase their talents.
Key craft positions in below-the-line work such as Costume, Art, Hair, Make-up Set Decorating and Paint may have portfolios of their previous work that highlights their creative and practical abilities.
Creative positions in Animation and Visual Effects will require a portfolio/demo reel of your work as part of the application process.
Music composers will have sample tracks or original compositions for a potential hirer to consider.
Your credits on film and television production are critical to showcasing your capabilities and creative skills. Consider listing yourself on IMDb, where you can build a filmography of your credits on productions.