Hello- How to fix Main URL(not show) in search engine results? actually before some days ago in Google search result show main URL like domain but now show internal page not main page so how to fix them please suggest.

Google has not indexed your website yet because it's too new

website isn't optimized for search engine crawling

Your keyword market is very competitive. You must do some keyword research and competition sites. you have to do white hat seo techniques with quality and unique content.