Hi Aspirant,

Core companies are the ones that specialize in particular sectors and are highly valued for their level of expertise and professionalism in their respective areas of operation. These companies offer jobs in core areas of engineering such as mechanical, electrical or infrastructure sector.

While ITES companies are  Information Technology Enabled Services companies. It is also called web-enabled services, remote services, or Tele-working company. ITES includes a large variety of different operations that uses information technology to upgrade the workability of an organization.

Hope this helps.

All the best!!