<el-input
  v-model="form.invitor"
  placeholder="PC端的自动取当前账号的手机号"
  readonly
  class="no-border-input"
/>

::v-deep(.no-border-input .el-input__inner) { 
  border: none; box-shadow: none; 
  padding-left: 0; /* 确保内容紧贴左边 */
}

dgq@dgqdeMac-mini spid-admin % yarn list --pattern element-ui
yarn list v1.22.22
└─ element-ui@2.15.13
✨  Done in 0.23s.

dgq@dgqdeMac-mini spid-admin % yarn list vue
yarn list v1.22.22
warning Filtering by arguments is deprecated. Please use the pattern option instead.
└─ vue@2.7.14
✨  Done in 0.24s.