1.方法一：

 <label v-for="(item,index) in createNumber" :key="index" >//createNumber是数组或者数字
                    步骤{{index + 1}}
                    <input>
                    <span class="add_icon" @click="createInput(index)"><i class="icon-ali-roundadd"></i></span>
                    <div class="arrow" v-if="index!==(createNumber.length - 1)">
                        <i class="icon-ali-refresharrow"></i>
                    </div>
                </label>

js部分

   createInput(index){
                this.createNumber.splice(index+1,0,index+1)
                //或 this.createNumber++

            }