We covered creating a Form in a previous article. In addition to creating questions for Reviewers, you can invite people to your team for the sole purpose of reviewing form submissions.
This article assumes you already know how to Add a Team Member. If you don't, check out How to Add a Team Member before continuing.
1) Click the Profile Icon at the top-right of the screen.
2) Select Manage Team from the dropdown.
3) Add a Team Member.
Within the team settings, enable both read and write access for the promote permission.
Note: Once you've invited the Reviewer, they'll only be able to view and edit information in Forms.