There are two ways to configure Google shipping settings.
1. Shipping information can be set from inside your Google Merchant account under Settings > Shipping.
There are countless ways to provide shipping information to users here.
For more information on the Google shipping, click here.
2. Setting a flat shipping fee to your feeds
To add a flat shipping rate to your Google feeds, click on the [open advanced command] box and type:
where # is the flat rate. Example:
Hit update and then regenerate the feed.
The shipping information for all products may look like this:
Essentially, all products have free shipping.