Shipping Policy
Go to tool & settings → select shipping & return

On shipping tab → Add shipping service

You need to entered 3 main details like Service coverage, Delivery times & Shipping cost
Service coverage : Add shipping service name (for eg. Delhivery, Bluedart etc ) & Countries

Delivery time : You can check these details on client website shipping policy page.
Confirm order cutoff time with client, add order handling time & transit time.
What is Order cutoff time ?
Order cutoff time allows you to set a time after which you will no longer process orders received on that day. For orders processed after cutoff time, one day gets added to the delivery time estimate.
Shipping cost :
If there is free shipping in website select Free shipping

If free shipping is available over a certain amount select first option

If shipping rate depends on the order value select Range based

And if there any flat amount select Flat Rate

Return Policy
Review the return policy on website

If the provided date is correct, you can accept & continue , will suggest to select edit & continue or start over then review your policy & save it.
Select country and add policy page url from website

Select yes if your client accept returns

Add Return window

Select the method how can customer return your products, most of the cases it will be by mail (courier), then add details of how will customer get the return label

Add Product condition for return

Add Return Fees if applicable for defective or remorse, if not select No cost and save.
Note : Please confirm all these details from the client.