Adding people from the same organization or company to projects

To add a bunch of people from the same company to your project at once, go to "Set up people", then click the "Or pick people from a company" dropdown and select the company you’d like to add people from:

After that, choose people from that company to be added to the project:

Once you have added those users, you can change their participation type to decide how they get notified of updates to the project: