You can enable Free Shipping on Easyship under your store settings in checkout settings under 'Connect' in your dashboard.
In settings, you can choose a name for your set up, which will be displayed on the main page if you have several different free shipping options.
You can choose which countries this setting should apply to. By default, the feature will have selected all countries. But you can also limit this to specific countries.
Minimum Order Price will decide on the basket value for free shipping to apply. Please note that this does not take into consideration any voucher-codes used.
Maximum Shipping Discount will set a limit on how much you wish to discount the least expensive option with. Meaning if you have certain destinations or orders which cause the cost of shipping to be high you can have a threshold to limit the discount.
A good example is if you wish to setup Free Shipping for Domestic without any maximum shipping discount. Then free shipping to certain regions but with a maximum shipping discount.
This would look something like below in the Rates at Checkout settings;