Members of the bulkadmin fixed server role can run the BULK INSERT statement.
Members of the dbcreator fixed server role can create, alter, drop, and restore any database.
The diskadmin fixed server role is used for managing disk files.
Members of the processadmin fixed server role can terminate processes that are running in an instance of SQL Server.
Members of the securityadmin fixed server role manage logins and their properties. They can GRANT, DENY, and REVOKE server-level permissions. They can also GRANT, DENY, and REVOKE database-level permissions. Additionally, they can reset passwords for SQL Server logins.
Members of the serveradmin fixed server role can change server-wide configuration options and shut down the server.
Members of the setupadmin fixed server role can add and remove linked servers, and also execute some system stored procedures.
Members of the sysadmin fixed server role can perform any activity in the server. By default, all members of the Windows BUILTIN\Administrators group, the local administrator's group, are members of the sysadmin fixed server role.
For details on role-level permission, execute sp_srvrolepermission rolename, e.g., sp_srvrolepermission processadmin
