Consider when your customers are the happiest. Maybe it’s when they’ve recently renewed their subscription with you, gave you a high NPS, or submitted a G2 review. Whatever it may be that makes them happy, these are the times to delight them — develop automation to send your customers an invite to your partner program during these times.
For example, if a customer just gave you a high NPS, ensure you send an automated email letting them know they can get paid for each person they refer by sharing a link.