Shopify can store password-protected customer information including identity, order history, and current order status. Customers with accounts will have the pre-filled, making the checkout process faster.
To use customer accounts you need to have the Online Store sales channel.
How to Enable Customer Accounts
STEP 1
From Shopify admin, click on Settings.
STEP 2
Click on Customer Accounts.
STEP 3
In the Accounts in Online store and checkout section, click Edit.
STEP 4
Update the settings and click Save to apply the changes.