Stakeholder engagement is defined in the GPP document as, “…processes through which trial funders, sponsors, and implementers build transparent, meaningful, collaborative, and mutually beneficial relationships with interested or affected individuals, groups of individuals, or organizations, with the ultimate goal of shaping research collectively.” Formative research can be regarded as one form of community engagement (a subset). Of note, formative research would be one of the first steps in community engagement and lay the foundation for engagement and open and trusting relationships.
I cannot directly answer this question as I am not currently a staff member executing clinical trials. However, from a Sponsor perspective, one of the most important things to do is make sure those involved with trial development are aware of the importance of formative research and encourage and help facilitate this work.