Not safe for kids under 18
eHarmony is a dating app launched in 2000, where users can upload and browse profile pictures and bio descriptions. If two users “match”, they can directly message one another. Sexual/Mature content is likely.

In-depth breakdown

Minimum Age Requirement
Messaging Capabillities
Users must pay to see profile pictures of other users. After both parties match, they can send messages to other users, even before both parties match. After matching, video and voice calls are accessible.
Location Sharing
Location is used to connect users within a certain radius.
Parental Controls
None, though Apple and Android parental controls could be used at the device level.
Many functions of eHarmony are behind a paywall.