RecruitingBehavioural interventionRe-Engaging AYA Survivors in Cancer-Related HealthcareThe goal of this clinical trial is to test the efficacy (how well they work) of different digital interventions that deliver information to adolescent and young adult (AYA) survivors of childhood cancer to promote re-engagement in cancer-related long-term follow-up care (LTFU). The main aims are: * To test the efficacy of adaptive interventions (AIs) that begin with low touch intervention (LTI) as compared to written information (WI) on attending an appointment, and self-reported self-management among AYA. * To identify the most efficacious second-stage strategy for those who initially schedule/attend an appointment (maintenance vs. step-up) and for those who do not (step-up vs. step-up maximum). * To assess multilevel factors contributing to the effects of re-engaging AYA and how best to integrate AIs into practice. Throughout the duration of the study, participants will complete four surveys, receive a series of interventions, and may be asked to participate in an interview (post-intervention).