You can create and be a part of multiple organizations in two ways:
👉🏼 Same email address & profile:
If you have one role and that role causes you to be part of multiple organizations (i.e. consultant, partner), you'll want to use the same email address for additional organizations. The benefits of this is that you can log in once and then toggle between the organizations by clicking on the organization name on the bottom of the side bar. A pop-up menu will show up and you can click on an another organization and start working there.
Organizations will operate completely separately, but you have the ability to toggle back and forth. Your profile will be the same for both.
👉🏼 Different email addresses and profiles:
If you have different roles at different organization and there isn't overlap, then you should use two separate email addresses. You'll need to log into one account and log into the other to access them. Or you can access them through two different browsers.