How to set Custom Robot txt and Custom robots header tags on blogger

Assalamu alaikum dear friends. Hope all are fine. Today i am gonna to showing how to set Custom Robot txt and Custom robots header tags  on blogger. This article help the beginner bloggers. Because Custom Robots header tags setting  is most important for every blogger. Custom Robots header tags play and important role on Google Search engine and this setting helps you on better SEO too. How to