we want to create user login in our website.
is it advisable to store user login credentials in sitecore?
what is the suggested approach to manager website user login credentials and authentication using sitecore
Default the login credentials are save* stored in SQL membershipAlso easy to create a new domain for your website login.See https://doc.sitecore.com/developers/90/platform-administration-and-architecture/en/create-and-edit-a-security-domain.html
If you want to use another database or provider than the Sitecore core db, take a look at the Sitecore Switching Provider.
* Note: default there is weak hash algorithm, change to stronger:see https://doc.sitecore.com/developers/91/platform-administration-and-architecture/en/change-the-hash-algorithm-for-password-encryption.html
Note: in Sitecore 9.1 there is no need to have a Sitecore Core database on your CD, of course you need it when you use the Membership of the Sitecore core DB