Contact access to their company's tasks

You can automatically grant external users or contacts access to all tasks in the Dashboard where their company is the counterparty. To do this, switch the setting Can see tasks where their company is a counterparty to Yes:

Then the contact will receive access to all tasks where their company is the counterparty. In terms of what they can do in these tasks, their access level is similar to that of a task participant. They will be shown in a separate section in the Permissions panel in each task's card: