As a web developer seeking a new job you will primarily be judged by the websites and code samples you have created or worked on. This is referred to as your portfolio.
You should host your portfolio online, preferably on a website you created on a domain you own.
Before you go out to find your first web development job you should have at least 3 good websites in your portfolio which showcase your focus.
If you plan to be a back-end web developer you should showcase your site architecture, Back-end developers should also have code samples in your portfolio to showcase any good or complex code you wrote for your sites.
Your portfolio will look very strong if you can showcase real sites you created for real clients. To get those clients at first we suggest you Build Sites for Free.