Adding Meta tags to every page is tedious and very repetitive that you just want it be done automatically. The good news is you can. With just a few lines of code and knowledge in C# and VB.NET, it is possible to add meta tags to your ASP.NET page dynamically. Dynamic meta tags mean that you don’t have to add meta tags one by one on every page. Every time a page is created or a blog post gets published, the meta tags you configure will automatically be inserted in the page or blog post.
If you want to add meta tags the fastest way possible for your aspx page read this: http://www.aspdotnet-suresh.com/2012/10/dynamically-add-meta-tags-to-aspx-page.html