How to remove “Archive:”, “Category:” etc. pre-title inserts in Archive Titles

If you would like to get rid of the “Category:”, “Tag:”, “Author:”, “Archives:” and “Other taxonomy name:” in the archive title, use this little function in your (child) theme functions.php file:

Code:

add_filter( 'get_the_archive_title', 'my_theme_archive_title' );
/**
 * Remove archive labels.
 * 
 * @param  string $title Current archive title to be displayed.
 * @return string        Modified archive title to be displayed.
 */
function my_theme_archive_title( $title ) {
    if ( is_category() ) {
        $title = single_cat_title( '', false );
    } elseif ( is_tag() ) {
        $title = single_tag_title( '', false );
    } elseif ( is_author() ) {
        $title = '<span class="vcard">' . get_the_author() . '</span>';
    } elseif ( is_post_type_archive() ) {
        $title = post_type_archive_title( '', false );
    } elseif ( is_tax() ) {
        $title = single_term_title( '', false );
    }

    return $title;
}

Update on July 21, 2019

If you wish to show the title of the Page set as Posts page (at Settings > Reading) automatically as the title on the Posts page, change the above code to

add_filter( 'get_the_archive_title', 'my_theme_archive_title' );
/**
 * Remove archive labels.
 * 
 * @param  string $title Current archive title to be displayed.
 * @return string        Modified archive title to be displayed.
 */
function my_theme_archive_title( $title ) {
	if ( is_category() ) {
		$title = single_cat_title( '', false );
	} elseif ( is_tag() ) {
		$title = single_tag_title( '', false );
	} elseif ( is_author() ) {
		$title = '<span class="vcard">' . get_the_author() . '</span>';
	} elseif ( is_post_type_archive() ) {
		$title = post_type_archive_title( '', false );
	} elseif ( is_tax() ) {
		$title = single_term_title( '', false );
	} elseif ( is_home() ) {
		$title = single_post_title( '', false );
	}

	return $title;
}

https://wpdevdesign.com/how-to-remove-archive-category-etc-pre-title-inserts-in-archive-titles/