Title Tag Support

title-tag.php

function theme_slug_setup() {
   add_theme_support( 'title-tag' );
}
add_action( 'after_setup_theme', 'theme_slug_setup' );

if ( ! function_exists( '_wp_render_title_tag' ) ) :
function theme_slug_render_title() {
    echo '<title>' . wp_title( '|', false, 'right' ) . "</title>\n";
}
add_action( 'wp_head', 'theme_slug_render_title' );
endif;