A URL that includes one or more parameters is considered to be dynamic since the page's content could be accessed via more than one URL. In contrast, a static URL contains no URL parameters in its construction.
Example of Static URL and Dynamic URL
For the Dynamic URL example, id=234982, ref=ppc, and lang=en are the parameters.
Dynamic URLs are typically less friendly for both humans and search engines. The presence of parameters can sometimes lead to long strings of irrelevant or unreadable text in the URL for humans. They can also potentially lead to duplicate content issues if not handled properly.
Static URLs, on the other hand, are easier for humans to read, type, and remember. They can help avoid potential duplicate content issues caused by using URL parameters.
Therefore, static URLs are generally recommended as a best practice, but if done correctly, using dynamic URLs will not hurt the SEO of your site.