SQL Server Service Accounts

Every service in SQL Server runs under security/Start up/Service  Account.

For Security reasons

• Use separate Service Account for each service.

Types of Account

• Local User Account
• Use this when SQL Server is local and serves applications on same server.
• Domain Account 
• for accessing Shared Fodler, Linked Servers etc.
• But, Not a good choice.
• Rather, create minimally previleged acount for every service before installation, and assign these account to specific service during installation, SQL server installion will take care of adding  these users to approprite group and will assign needed permissions.

Note: After Installion, If service account need to be changed always change it via. "SQL Server Configuration Manager".