element-plus/docs/examples/select/custom-template.vue

<template>
  <el-select v-model="value" placeholder="Select" style="width: 240px">
    <el-option
      v-for="item in cities"
      :key="item.value"
      :label="item.label"
      :value="item.value"
    >
      <span style="float: left">{{ item.label }}</span>
      <span
        style="
          float: right;
          color: var(--el-text-color-secondary);
          font-size: 13px;
        "
        >{{ item.value }}</span
      >
    </el-option>
  </el-select>
</template>

<script lang="ts" setup>
import { ref } from 'vue'

const value = ref('')
const cities = [
  {
    value: 'Beijing',
    label: 'Beijing',
  },
  {
    value: 'Shanghai',
    label: 'Shanghai',
  },
  {
    value: 'Nanjing',
    label: 'Nanjing',
  },
  {
    value: 'Chengdu',
    label: 'Chengdu',
  },
  {
    value: 'Shenzhen',
    label: 'Shenzhen',
  },
  {
    value: 'Guangzhou',
    label: 'Guangzhou',
  },
]
</script>