The domain authority is a measuring metrics by Moz, which is a third-party SEO tools provider. There are no official platforms where you can easily find the overall optimization of your website.
Most webmasters have to use this measuring number to know their efforts and check their efficiency.
For this, the Moz DA number
is beneficial as it is generated based on multiple algorithms that are based on the SEO of your site.
When getting your site edited by the SEO implications, the Domain authority will automatically help you to find if you are in the right direction.
For instance, you can use the online tools to check DA PA
to know the optimization level of your site. Later on, after applying, you should measure again to know did SEO affects your site positively or negatively.