Maybe, you will receive an invitation from TrustRadius over the email to write review of a software you are using such as Zoho CRM. Or say if you are a member of IBM Community, you will find an invitation to write a review and be rewarded with 25$.
It is imperative that you have a credible Linkedin profile as I understand they go through your Linkedin profile to verify authenticity. This is also true for other similar software review sites such as G2, Gartner, SoftwareReviews, and Capterra.
If you do not have any such invitation link, signup and write your first review even if that is not paid. Hopefully, you will later receive invitation links to write reviews with rewards.