WordPress automatically adds a wlwmanifest link to your site header for Windows Live Writer support. This is a link tag with a reference to your site's wlwmanifest.xml file: Like. <link rel="wlwmanifest" type="application/wlwmanifest+xml" href="https://ecaddons.com/wp-includes/wlwmanifest.xml" />
There are two ways.
1. Custom code in function.php