EMITS is the system used by ESA for publishing Invitations To Tender and information about the ESA procurement process. EMITS also allows other Entities outside of ESA to manage their Invitations To Tender in a way that is similar to the one adopted by the Agency.
The EMITS user manual is available at: http://emits.sso.esa.int/emits-doc/emitsdata/help/HelpGen.htm#