Please help me, dose anyone can give an example (vue-cookies or axios …)
i don’t see the example in ionic document 
Same way you always would. https://v3.vuejs.org/guide/plugins.html#using-a-plugin
How can I add Vuex? This code does not work.
import Vuex from 'vuex'
...
const app = createApp(App)
.use(IonicVue)
.use(router)
.use(Vuex)
;
// Vuex 4.x (for Vue 3)
import { createStore } from 'vuex'
import { createApp } from 'vue'
const store = createStore({
state () {
return {
count: 1
}
}
})
const app = createApp({ /* your root component */ })
app.use(store)