Add component MyPage in index.js

src/router/index.js

 import { createRouter, createWebHistory } from 'vue-router'
 import Home from '../views/Home.vue'
+import MyPage from '../views/MyPage.vue'
 
 const routes = [
   {
@@ -14,6 +15,11 @@ const routes = [
     // this generates a separate chunk (about.[hash].js) for this route
     // which is lazy-loaded when the route is visited.
     component: () => import(/* webpackChunkName: "about" */ '../views/About.vue')
+  },
+  {
+    path: '/mypage',
+    name: 'MyPage',
+    component: MyPage
   }
 ]