Largest Contentful Paint (LCP) is a metric that tells you how fast the first largest element loads on your page. It can be anything from an image to a block of text on the first section of your site page.
No one likes slow-loading websites. High LCP times create poor user experiences, so the lower it is, the better. Search engines can even penalize web pages with slow LCP and load times.
You can use Google’s PageSpeed Insights and GT Metrics to measure LCP.