What Happens to Bookmarks, Forms, and Metadata When Merging PDFs

What Merge PDF actually does

NexKit's Merge PDF tool works by copying each source file's pages, in order, into one new output document - the underlying mechanism reads each page's own visible content and places it into the combined file. This copies page content faithfully, including most annotations and markup drawn directly on the page, but it copies pages, not entire documents. Anything that lives at the document level rather than on an individual page - a bookmark panel, a fillable form's field logic, a title/author metadata record - is a property of the whole file, not of any single page, and page-copying has nothing to carry it over with.

This distinction - page-level content versus document-level structure - explains every specific behavior in the rest of this guide. It is worth understanding once instead of memorizing each case separately.

Page order and mixed page sizes

The merged PDF follows the order shown in the file queue, top to bottom, exactly as displayed before you click merge - nothing is reordered automatically based on file name, date, or content, so the order you see is the order you get. Drag a file by its handle or use the Up/Down controls, and the queue updates immediately so you can verify the new order before merging rather than after.

Each page keeps its own original size, orientation, and rotation in the merged output rather than being resized, cropped, or rotated to match the other pages - a landscape spreadsheet export merged next to a portrait letter will still display as landscape at its original size in the combined file. A merged PDF built from mismatched sources can therefore look visually inconsistent when scrolling through it, even though nothing was damaged or altered; that is expected behavior for this tool, not an error to troubleshoot.

Bookmarks are not preserved

Bookmarks and named outlines - the clickable table-of-contents panel some PDF readers show alongside the page view - are not created or carried over by this tool. The merged PDF will not have a bookmark panel even if one, several, or all of the source files did. This follows directly from the page-copying mechanism: an outline is a document-level index into a specific file's pages, and once those pages are placed into a new combined document, the original outline's page references no longer correspond to anything.

If a bookmark panel matters for how the merged file will be used - a long combined report someone needs to navigate quickly - plan to rebuild it manually in a PDF editor after merging, or use a dedicated PDF outline/bookmark tool on the finished merged file.

Form field interactivity is not preserved

If a source PDF contains an interactive fillable form, its field content and visual appearance are copied onto the page like any other page content, but the field typically stops working as an interactive, fillable field once merged - what you see is a faithful visual copy, not a functioning form. This is the same page-versus-document distinction: interactive form behavior depends on a document-level form definition (an AcroForm structure) that page-copying does not carry over along with the page.

If the merged file needs to remain fillable - combining a cover sheet with a form someone will fill out digitally - review the result after merging and, if the fields no longer work, rebuild them with a dedicated PDF form tool rather than assuming the merge preserved them.

Document metadata is not copied

Document-level metadata from your source files - title, author, and creation date - is not copied into the merged file. The output starts as a fresh document with its own metadata rather than inheriting any source file's. If a specific title or author needs to appear in the merged file's properties, it needs to be set separately after merging, in a PDF editor or metadata tool, rather than assumed to carry over from whichever source file it originally belonged to.

A practical preparation checklist before merging

Confirm the queue order matches what you actually want before clicking merge - the tool will not reorder anything for you, and fixing order after the fact means starting over. If any source file has a bookmark panel, a fillable form, or specific metadata you need in the final file, decide now whether you will rebuild it after merging or whether it genuinely does not matter for this particular combined document - both are reasonable answers, but deciding in advance avoids a surprise later.

After merging, open the result and check the first and last pages, confirm each source document appears in the correct position, and if the source files had mixed orientations, expect - and do not be alarmed by - the visual inconsistency described above. Keep your original source files until you have confirmed the merged file meets your needs; merging here does not modify your originals, but it also is not reversible from the output side.

Frequently Asked Questions