post title replace homepage title and no title on amp homepage

Do you have a link?

For the homepage, edit the front page under pages and add the title, description. Also in Settings -> Simple SEO enter the default SEO information to use incase there is none. Does this help?

here is the link https://www.brightmediapakistan.com/

On your default post page, in hte wp-admin edit the meta information on that page. Since your post page is your homepage, then the homepage meta information needs to be placed there.

but how sir what option should i go for edit

You need to place the meta information on the post page.