What a WordPress SEO plugin is for
WordPress does not, out of the box, let you control the title tag Google displays, generate a proper XML sitemap, add structured data, or manage redirects when a URL changes. An SEO plugin fills those gaps. That is the whole job. And it is a job of removing obstacles, not creating advantages.
Worth being clear about that, because plugin marketing implies otherwise. Every competitor ranking above you also has correct titles and a working sitemap. The plugin gets you to the starting line; it does not run the race.
What the free version covers
Unusually much. Rank Math's free tier includes several things rivals charge for, most notably the redirect manager and the eighteen schema types.
Per-post control of title tags and meta descriptions, with templates so archives and categories are handled automatically rather than one page at a time.
Generated and updated automatically, with granular control over what to include. Submit it once to Search Console and forget it.
Eighteen structured-data types in the free tier, applied without writing JSON-LD. This is the feature most competitors reserve for paid.
Create and manage 301s inside WordPress. Essential after any URL change, and free here where several rivals charge for it.
Logs the URLs visitors and crawlers hit that do not exist, so you can redirect the ones that matter instead of guessing.
Connects both and surfaces the data inside WordPress. Convenient, though the real reports still live in the tools themselves.

