How to Upload pdf, xls, xlsx, doc, docx in Laravel and Vue.js

My Code is below but it's not working. I can upload Image with base64 formate and successfully store on Laravel backend but I'm struggling to upload other file formates in Laravel and vue.js. Anyone can help please?

.vue file

<template>
  <div>
    <form enctype="multipart/form-data" @submit.prevent="handleSubmit">
      <div class="form-group mb-4">
        <label>Institute Prospectus</label>
        <label class="custom-file-container__custom-file">
          <input
            type="file"
            class="form-control-file"
            @change="onChangeProspectus"
          />
        </label>
      </div>
    </form>
  </div>
</template>

<script>
export default {
  data() {
    return {
      institute_prospectus: "",
    };
  },
  methods: {
    handleSubmit() {
      let data = {
        institute_prospectus: this.institute_prospectus,
      };
      axios.post(data, "/add-institute")
        .then(() => {
          console.log("Success");
        })
        .catch((err) => {
          console.log(err);
        });
    },
    onChangeProspectus(event) {
      let file = event.target.files[0];
      this.institute_prospectus = file.name;
    },
  },
};
</script>

InstituteController.php

public function add_institute(Request $request) {

    $prospectus_file = $request->institute_prospectus;
    if ($prospectus_file) {
        $ext = substr($prospectus_file, strrpos($prospectus_file, '.', -1), strlen($prospectus_file));
        $name = time().'-'.$slug.".".$ext;
        $upload_path = 'backend/files/institute/';
        $prospectus_url = $upload_path.$name;
        $prospectus_file->move($upload_path,$prospectus_url);
    }
}

via Chebli Mohamed