Solution:
You can try this
function get_user_information() {
if ( is_user_logged_in() ) {
$current_user = wp_get_current_user();
echo ( 'Welcome, registered user!'. esc_html( $current_user->user_email ) );
} else {
echo( 'Welcome, visitor!' );
}
}
add_action( 'loop_start', 'get_user_information' );