First consortium members need to submit a Declaration of Honour to the European Commission. This declaration ensures that all beneficiaries comply with the rules and are not in a situation that would exclude them from receiving EU funding (e.g. bankruptcy). This is followed by the Consortium Agreement between consortium members and Grant Agreement between consortium and European Commission.
*In case of a “Coordinated Call” (with MIC/NICT) between the EU and Japan, a Coordination Agreement replaces the Consortium Agreement for Japanese participants.
In addition, a Letter of Intent could be signed before submission of the proposal. This is not mandatory but usually a coordinator asks all participants to sign and submit this before application. The letter shows that your organization has the explicit intention of applying for the project.