If your customers create an account with your store, then they can add their address information to their account so that it autofills during checkout. They can also view their order history with your store, and see the current order status for any purchases they make. For more information, see Customer accounts.
From your Shopify admin, click Settings, then click Customer accounts.
At Accounts in online store and checkout, choose "Show login link in the header of online store and at checkout".
Shopify provides a number of options for enabling customer accounts and you can find out more about this in their help article. See Shopify Customer Accounts guide here for more details about enabling this setting on your store.
