Can other partner organisations get access to the project proposal account I have created?

The coordinator can decide upon the policy to be used in the project. 

If partners should be able to edit their data check the "Enable partner modification" field in the project edit view and save the project. In the "Consortium" section of the project view you can check if partners will be able to edit their data. By de-selecting this option partners will still have access to the project and their data but will not be able to edit. 

For every project partner add any number of partner "members" in the project partner view. They will automatically receive an email with their access data. Each partner will only able to modify "his/her" details but NOT the project details (which can be done by the coordinator only).