WordPress allows for multiple users to work on one site so you can have a team of people to collaborate on your project. You can invite people by selecting the Users option from the Admin panel and then clicking on the Invite button at the top of the People page.
WordPress offers the ability to add users to your site with different roles. If you need someone else to help manage the site, you can add them as an Administrator. You can also add someone as an Editor so that person can manage all of the posts and pages but can't access other admin settings like Appearance or Settings. Maybe you want someone to be able to just add content and write for your site. You can add that person as an Author or Contributor. An Author can write, edit, upload items and publish their own posts. A Contributor can write and edit their own posts, but does not have the ability to publish them. These options allow you to collaborate on your own terms.