How to: Create a Credential (SQL Server Management Studio)
A credential is a record containing the authentication information needed to connect to a resource outside of SQL Server. Most credentials consist of a Windows login name and password. On Microsoft Windows Server 2003 and later, the password may not be required.
A single credential can be mapped to multiple SQL Server logins. But a SQL Server login can be mapped to only one credential.
Only users with ALTER ANY CREDENTIAL permission can create or modify a credential.
In Object Explorer, expand Security, right-click Credentials, and then click New Credential.
In the New Credentials dialog box, in the Credential Name box, type a name for the credential.
In the Identity box, type the name of the account used for outgoing connections (when leaving the context of SQL Server). Typically, this will be a Windows user account. But the identity can be an account of another type.
In the Password and Confirm password boxes, type the password of the account specified in the Identity box. If Identity is a Windows user account, this is the Windows password. The Password can be blank, if no password is required.