Adding section headers to a form can improve its readability by breaking it into logical chunks and providing context for the users. Section headers can also help users scan the form and find the information they need faster. Section headers can also reduce the cognitive load and increase the completion rate of the form .Reference:

: Salesforce Certified User Experience Designer Exam Guide, Section 3.2: Design for readability and clarity

: UX Designer Certification Prep: Design for Readability and Clarity, Unit 2: Design for Readability and Clarity

This allows users to quickly scan the form and identify the relevant fields, reducing the cognitive load and improving the overall user experience. Salesforce documentation statesthat ''by grouping related fields into sections, you can make your forms easier to read and understand'' [1].

[1]https://help.salesforce.com/articleView?id=forms_design_best_practices.htm&type=5