If I have polygons containing data, if point is placed within that polygon on Survey123, I would like to use attributes from that polygon to populate Survey123 fields.
Is this possible???
This is possible through a beta feature - the creation of a custom function. This is documented in the Early Adopter Community, and includes a point-in-poly data lookup example. Please see Welcome to our Feedback Community for more information.
maybe you can also create a Custom Pop-up (Crafting custom attribute displays in pop-ups) for your geometry in your WebMap, where you can insert a custom URL (https://community.esri.com/groups/survey123/blog/2016/07/30/understanding-survey123s-custom-url-sche... ) that can invoke Survey123 App with pre-populate questions with value from fields from your polygon.
Something like this: