You can configure the list form in a list or library with a custom header, footer and the form body with one or more sections with fields in each of those sections. The form configuration does not change the data in the list item or file; it only changes how the form is displayed to users who browse the list or library. Anyone who can create and manage views in a list can use form configuration to configure the form with header, footer and body with sections.

To configure a form, you will use JSON formatters that you are already familar with when formatting a column or a view in a list or libary. Form configuration allows for certain predefined elements and attributes to build the custom header, footer and body with one or more sections.

• https://docs.microsoft.com/en-us/sharepoint/dev/declarative-customization/list-form-configuration

• https://pnp.github.io/List-Formatting/formsamples/