In order to setup Google Tag Manager tags for Rakuten, we'll need to have a Rakuten Merchant ID & Sitewide Tag

How to Find Sitewide Tag:

Step 1: Contact Rakuten's Support Team

Rakuten will also supply you with a unique sitewide tracking code for your store that is unique to your account.

How to Find Merchant ID:

Step 1: Log into your Rakuten Account

Step 2: Your Merchant ID will be located on the top right corner

At the top right corner of your page, you'll see "MID 11111". This is your unique Merchant ID. This should be a 4 or 5-digit Merchant ID.