Three layouts covering the three situations organisers actually hit: one match, one whole session, and one court running all day. Pick a sheet and print it — nothing to download.
One row per completed game. Keep the running differential — it is the tie-breaker you will need.
Tape one to each court's fence. Players fill it in themselves; you collect them at the end.
Almost every lost result comes from the same three failures: the sheet stayed on court after the players left, two courts finished at once and one score got announced but not written, or the handwriting was ambiguous by the time you compiled standings. Numbering rows and collecting sheets per round fixes most of it.
If you are compiling results into a table anyway, entering them once on a phone as each game ends removes the compilation step entirely — and every player sees the updated standing immediately instead of at the end. See tie-breaker rules for what you need to record to settle a tie fairly.