If you want to insert the same tags to every post on your blog post, you can set it to be done automatically using PHP. Using this simple snippet, all tags will be added automatically on post save and publish.

Everytime you save a post save_post action runs. Using an action filter, we will insert our tags into our post. To insert tags, we can use wp_set_object_terms. This function is a great tool to insert tags, categories, terms on the background.

Here is the snippet to insert post tags programmatically on save post.

add_action( 'save_post', 'auto_add_post_tags' );
function auto_add_post_tags( $post_id ) {
	if ( !wp_is_post_revision( $post_id ) ) { //verify post is not a revision
		$tag_ids = array();
		
		if( !has_term( 2610, 'post_tag' ) ) { $tag_ids[] = 2610; }
		if( !has_term( 2611, 'post_tag' ) ) { $tag_ids[] = 2611; }
		if( !has_term( 2612, 'post_tag' ) ) { $tag_ids[] = 2612; }
		if( !has_term( 1337, 'post_tag' ) ) { $tag_ids[] = 1337; }
		
		if( count( $tag_ids ) > 0 ) {
			wp_set_object_terms( $post_id, $tag_ids, 'post_tag', true);	
		}
	}
}

Don’t forget to change tag ids on the snippet. Enjoy!

(image credit)