Hello jayapal13
It seems there are multiple Headers in your theme, one is marked as Display:none which is showing for fraction of sections, trying deactivating your theme and activate some default theme and see if problem persist.
Also, it seems you are using some paid ThemeForest theme so trying upgrading your theme to its latest version in case theme developer have solved the issue.
Hope this information helps.
Thanks.
@kartiks16
Is there any query to remove the main menu from the site.
Hello jayapal13
If you bit aware about code, I would suggest to write the code which will hide the div from rendering, or else you can also opt of the CSS tweak.
Try to use Visibility:hidden with display:none if that help.
Let me know if this helps.
Thanks.
Hello jayapal13
Happy to know that solution helps.
You can mark it as resolved if the problem has been fixed.
Thanks.