first upload all files

Themes/Storefront/views/public/cart/index/coupon.blade.php

@@ -0,0 +1,37 @@
+<div class="coupon-wrap">
+    <form @submit.prevent="applyCoupon">
+        <div class="form-group">
+            <div class="form-input">
+                <input
+                    type="text"
+                    v-model="couponCode"
+                    placeholder="{{ trans('storefront::cart.enter_coupon_code') }}"
+                    class="form-control"
+                    @input="couponError = null"
+                >
+
+                <span
+                    class="error-message"
+                    v-if="couponError"
+                    v-text="couponError"
+                >
+                </span>
+            </div>
+
+            <button
+                type="submit"
+                class="btn btn-primary btn-apply-coupon"
+                :class="{ 'btn-loading': applyingCoupon }"
+            >
+                {{ trans('storefront::cart.apply_coupon') }}
+            </button>
+        </div>
+    </form>
+
+    <span
+        class="error-message"
+        v-if="couponError"
+        v-text="couponError"
+    >
+    </span>
+</div>