Excel

A spreadsheet has no pages until you make it have them

A sheet is an endless grid. A PDF has edges. Something has to decide where the cuts fall, and left to itself it rarely chooses well.

The usual result is a table split down the middle, with the last three columns alone on a second page and no headers to say what they are. Nothing in the conversion causes this: the cut points come from the spreadsheet's own print setup, which most people never open.

Set the print area

Tell the sheet which range is the document. Everything outside it stops existing for the conversion.

Fit to width

One page wide, as many pages tall as it needs. This single setting fixes most split tables.

Repeat the header row

So page four still says what the columns are.

All three live in the spreadsheet, before any conversion happens. Set them once and the PDF comes out right every time afterwards.