I have a big project creation form having atleast having 30-40 fields where i have already grouped the relevant fields as a set(splitting into 3 columns) with proper headers, but still i have a long form.
My Question is where should i place the Save/Cancel/Edit buttons..? I am showing Edit only in read only mode. I have placed bottom left hand corner as user fills the form from top to bottom and hit save. Sometimes, they might not fill all the fields just fill the top section want to save the form, so in that case the user needs to scroll all the way to bottom.
Is there any data or research supporting this pattern? Is there another approach you recommend? I'm not as interested in official guidelines, as much as research-backed principles and the corresponding sources.