Core Web Vitals are the speed metrics that are part of Google’s Page Experience signals used to measure user experience. The metrics measure visual load with Largest Contentful Paint (LCP), visual stability with Cumulative Layout Shift (CLS), and interactivity with First Input Delay (FID).
Just to set expectations, remember that there are over 200 ranking factors. I wouldn’t expect much improvement from improving Core Web Vitals. It’s unknown how much they will impact rankings but it’s not likely to be a strong signal, especially considering many of the page experience components were already used by Google to determine rankings.