You will need a Google Merchant account, if you do not have one you can register here.
If you are using the Advanced Custom Fields PRO in your WordPress, make sure it is in current version. Otherwise, when you turn on Google Merchant XML, you'll see the message:
Google Merchant XML requires ACF PRO x.x.x or newer. Update to the latest version of ACF PRO.
And you will not be able to work with Google Merchant XML.
Google Merchant Dashboard
Go to menu Google Merchant to find all feeds and plugin settings:
Adding Google Merchant Feeds
You may add multiple XML feeds with unlimited number of products.
You may update single feed, multiple feeds or choose automatic feed update.
Quick Edit Feeds
Automatic Feed Update
You may choose (we recommend this) to automatically update feeds when a product is added, edited or deleted. This also includes quick and bulk product edits.
Sometime you will need to map product attributes from your WooCommerce store to Google Merchant Center attributes.
Product variation are displayed in the XML file by default. Each of the variation is presented as a separate product. If you want Google Merchant Center system to identify variations as products from one group, please use the item_group_id parameter.
Selecting the option Exclude variants from feeds will hide all varaible products from the XML file.
Exclude shipping info from all feeds
If you do not want to send shipping information to Google Merchant Center, please select this setting:
If you want to put shipping information manually in Google Merchant Center, please follow this instruction.
Adding feeds to your Google Merchant Center
This is beyond the plugin usage and shows how to add a feed to your Google Merchant account. Feeds will be fetched once a day.
Log in to your Google account here.
List of attributes supported by the plugin
You can find more about attributes here.