A call for feedback is a post that you share internally once the design you’re working on is ready for feedback.
This could be multiple posts, each at a different stage in the design process, or it could just be a single post.
The goal of the post is to solicit feedback from folks outside of your design org.
It’s helpful to start by giving some context around the project. What is the problem you’re trying to solve? What customers will be affected. What impact will this project have?
Then you can showcase your design through a series of screenshots, gifs, videos, or prototypes. It can also be helpful to link to other posts related to this project and to outline open questions you have and the list of known issues. Finally, before you wrap up, just be sure to be explicit about the type of feedback you’re looking for.