How can I offer free shipping to a specific customer group?

[AngelaShum]

How can I set a free shipping for a group of customer? 

For example : customer tagged "VIP", then all order from VIP can be "free shipping" without amount limited. 

[DigitalArtisans]

Hello @AngelaShum !

In order to do this, you'll need to enable a third-party shipping app. Bespoke Shipping looks to do exactly what you need. You can set a special rate based on their customer tag. For example, you could tag your VIP customers with VIP and then set a free shipping rate for anyone with that tag.
Your store will need to have Carrier Calculated Rates addon enabled on your store.
Shopify Support can to do it for 20 Usd per month.

Hope this helps!

Thanks,
Digital Artisans