Ahref is a very useful site where you can check the useful On-page optimization. One of the most important part is On-Page SEO where you need to utilize some detailed information to rectify the selected benchmarks for On-Page. In another words it gives you opportunity to Optimize Off-Page SEO as well.  You can use this site for any website it doesn't necessary that it requires only specific website like WordPress or something, NO! you can use it on any site! Try it today!