What proportions to observe for adaptability?

Question

Design

Good afternoon! I'm interested in the question. What size should the canvas be in Adobe Illustrator in order to draw a high-quality header for the site and so that it does not lose quality when viewed on different devices. Indents from the edge, etc., etc.
Many thanks in advance to all who replied!

Answer 1

Size doesn't matter if you're drawing with vector graphics.
And in order for a normal image to be of the best quality, then just set it to 4k (or a higher resolution), plus on smartphones and devices with a display smaller than the monitor, it will just look like a candy.