Should interaction be defined in the PRD or defined by designers in Figma?

I’m a new designer and in a newly established develop department.
I’m the only designer in a 60 members dev group, so I need to do all things by myself.
We dev a product but lack a lot, include interactions.
While, the PMs, didn’t define interactions in PRD, and I don’t know what customers prefer, so the only thing I can do is to have a free creation during my UI works.

Is there any…order or default process or example PRD that include interactions?