Well, in my more optimistic moments, I'd say from word of mouth. For example, I'm particularly drawn to Bumble and Hinge because I know people who have met their partners on those.
But I've deep dived into the data, and there are systemic issues on the apps that a goodwill practitioner could fix. They do a lot that's just to keep us engaged, and it's either not going to help us find love or, sometimes, it actively hinder us from finding love. I actually have a full write up on my findings coming out soon.
All in all, it's something of a mixed bag. The way I lead my life, I'd probably die alone without them, so I'm grateful. But something as important as a facilitator of love between masses of people would ideally be handled in a way that puts the success of the lovers over profit. But who am I kidding? When has something like that ever happened?