Generally, to add information to a PDF, you'll want to, in Form Builder, at the end of your form, create a section, say "Confirmation", with an Explanatory Text field. That field allows you to write text interleaved with dynamic values. In the Section Settings, check the box "Page break before" to have that section on a new page. Also, under "Visibility", use `fr:mode() = 'pdf'` so the section only shows in the PDF.
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