For an SharePoint Installation always create specials service accounts, each with it’s own email account.
|sp_sql||Service account for SQL Server services: MSSQLSERVER, SQLSERVERAGENT
If you have already SQL Server somewhere running on a neat cluster, you don’t have to care about. But you should have access to your instance with SQL Management Studio.
|sp_admin||This account is local admin on your sharepoint servers (WFE, App). It’s a Domain-User account.
This account is not a local admin on your SQL machine!
Use it to install everything (SharePoint itself, Patches, Add-on and so on). Run the config wizard with this account. Simply: if you want to install something for SharePoitn log in with this account.
|sp_farmadmin||This account is local admin on your sharepoint servers (WFE, App). It’s a Domain-User account.
Use this account when the config wizard asks for the database access acount.