There are two types of profiles on Crystal: Assessments and Predictions.
Assessments are profiles created by taking the personality assessment on Crystal.
When someone creates a free Crystal account and completes the free personality assessment they then have an assessment profile.
If you want to invite co-workers or job candidates to take an assessment so you can view their profile, you'll need a Team Premium or Hiring Premium account. Once you do, you can invite co-workers or create a job.