Visit figma.com open_in_new.
Select Get started for free, then follow the prompts.
Make pretty stuff (on the web or locally).
Need something more like Adobe Illustrator?
Try Inkscape open_in_new.
Both allow you to create vector graphics. I love the usability and shareability of Figma. Inkscape lacks a web app option, but is more comparable and robust for Illustrator style projects.
There are also more vector graphics editor options open_in_new