1、关联调用，隐藏上传框

<button onclick="chooseFile.click()"> 上传文件 </button>
<input type="file" id="chooseFile" style="display:none;">

参考 https://blog.csdn.net/qq_28306215/article/details/85322944

2、使用 label for 指定标签

css

.upload_bp input[type='file']{display: none;}
.loadbp{
    padding: 0 30px;
    height: 40px;
    border: 1px solid #dd5923;
    color: #dd5923;
    font-size: 16px;
    display: flex;
    align-items: center;
    box-sizing: border-box;
}
.loadbpsuccess{
    height: 40px;
    background: #f5f7f9;
    border-radius: 2px;
    font-size: 16px;
    line-height: 40px;
    padding: 0 30px;
    color: #262626;
    letter-spacing: 0;
    text-align: center;
    margin-left: 15px;
    box-sizing: border-box;
    position: relative;
}
.loadbpsuccess span{
    font-size: 20px;
    color: #000;
    position: absolute;
    top: -10px;
    right: 2px;
}

html

<div style="display:flex;align-items: center;">
     <label class="upload_bp" for="fileinp">
          <input type="file" id="fileinp">
          <p class="loadbp"> 上传附件 </p>
      </label>
      <p class="loadbpsuccess"> 附件 1.pdf <span>×</span></p>
  </div>

参考：https://blog.csdn.net/Dilemma_me/article/details/100120542