Upselling with Shopify Product Bundles is a means of selling many different items as a single combined pack or bundle through a Shopify website. Bundles are the most effective way when each item in the bundle sells for less than what the shopper expected to pay. You can see a bundle package in Frequently Bought Together section on the product page. 

This writing will show you how to create the product bundle fields to product metafields in Shopify. 

Step 1. Install app "Metafields & Custom Fields"

- You can download and install the app here

- Read the instruction of the app here

Step 2: Access the App and Create Product bundle fields

#1. Open App

Login to your Shopify Partner account >  Go to Apps section > Open ACF app (Metafields & Custom Fields)

#2. Create Product bundle fields

• Once you access the app, you will be directed to the Configuration section > You scroll down to see a list of section to customize > Choose Product block 
• The product editor will appear, you need to drag the Product fields at the Custom Field Types column to the Product fields box 

#3. Insert information to the Popup

• Tick to Hide field or Repeatable field
• Namespace: this is an optional namespace (logical grouping) for the field. Default name for this is "arena" if you leave it blank. Limit from 3 to 20 letters
• Key: a unique key for the field (3-30 letters)
• Label: label for the fields when editing for the product (No HTML tags)
• Instruction: instructional text shown for the fields on product 
• Field applies to: choose a type to apply this fields to the related product 
• Tick to Allow selection of multiple values
• Click Save

#4. Add a Bundle Product to a Specific product

• Go to Apps section again > Get into the ACF app > Switch to Products area > and choose a specific product that you're going to attach a bundle product to 

• Scroll down and you will see the bundle product field that you've just created 

• Click on the "Product Selection" button and choose products that you want to add to the bundle product list

• Finally click on "Add" button and SAVE

So that is how to create a bundle product field with metafields app. Wish you can increase sale with this amazing feature.