Page one for this question collapses to a single binary: PDF if someone is reading the script, FDX if a pipeline is going to parse it. Final Draft's own guidance says exactly that, and so does every export guide that compares the two formats. The binary is correct and it is also not the whole delivery: a script rarely goes to only one kind of recipient. A manager, a blind-read contest and a production office reading the same PDF still need three different title pages.
The Delivery Register holds one row per actual recipient, because the requirement is never just the file format. A literary manager wants a full title page with contact information. A blind-read fellowship like the Nicholl wants a title-only page with no identifying information anywhere in the file, a stricter, separate requirement from PDF versus FDX. What every export guide skips: a PDF commonly carries the writer's name in its own file properties even when the visible title page is blank.
Once a script is optioned and locked for pre-production, delivery becomes revision tracking. The WGA's own standard color order runs White, Blue, Pink, Yellow, Green and Goldenrod, and new material spills into lettered pages without shifting pages downstream. On a worked lock here, a 104-page feature, three revisions add two lettered pages and retire two scenes as OMITTED, landing the script at 106 locked pages. Earlier in a project, a beat sheet or a pitch and treatment pack fits better; this one starts once delivery, not scheduling and budgeting, is the open question.