includes_header.php

<!DOCTYPE html>
<html>

<head>

  <meta charset="utf-8">
  <title>
    Sistema de cadastro de clientes
  </title>
  <!--Importando icones-->
  <link href="https://fonts.googleapis.com/icon?family=Material+Icons" rel="stylesheet">
  <!--Instalando materialize-->
  <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/materialize/1.0.0/css/materialize.min.css">

  <!--Let browser know website is optimized for mobile-->
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
</head>

<body>