Search Console is a free dashboard from Google for website owners. Once you prove you own the site, it shows which search phrases your pages appear for, how often they are shown, how often they are clicked and your average position.
It also reports problems: pages Google could not index, mobile usability issues, Core Web Vitals, security issues and any manual penalties. You can submit your sitemap there and ask Google to recheck a page after you fix it.
It is different from Google Analytics. Search Console tells you what happens in Google before someone clicks; Analytics tells you what they do on your site afterwards.
It is the only place you get Google's own data about your site, for free. If an agency or SEO provider cannot give you access to it, or will not show you what it says, treat their reports with caution. It is your site; you should own the account.