I watched people create forms in a study and saw a creative workaround for an unclear feature.
The model that the participants were copying had a Submit button, and the program automatically inserted one in the form. That seemed like a convenience, but there was no way for users to know that would happen.
There was no way to insert the button because it was automatic. One creative person inserted a text box and made the default value be “Submit”:
The lesson is that people often do things we don’t expect. Sometimes customer research like this usability study is the only way to find that out and prepare for it.