To add and customize additional subfields to the Name field, access the form builder, select the field in the Form Editor and go to the Edit Field panel (left side). Under Additional subfields, you can add a small dropdown list for the title and two input boxes for initials and middle name.
To customize Name subfields, keep in mind that:
In Submissions, a new column will appear for each subfield when enabled in the Form Editor.
To change the placeholder texts inside the fields (Title, First, Initials, Middle, Last), go to Translations and add your own text.