The cover letter

For journals, a cover letter to the editor comes with your submission. Editors are busy; the letter helps them decide quickly whether to send your paper for review.

What to include

1. The basics: the title, the article type, and that it is submitted to this journal.
2. The main finding in one or two sentences, in plain language.
3. Why it fits this journal: why its readers will care.
4. Required statements: that it isn't under review elsewhere, any preprint, conflicts of interest, data availability.
5. Optionally: suggested reviewers (with no conflicts) or reviewers to avoid, with reasons.

Keep it short

One page. Don't paste the abstract. Don't oversell: editors have seen "groundbreaking" thousands of times.

Example"We submit our manuscript 'Colour augmentation recovers accuracy for small leaf-disease datasets' as a Research Article. Using 12 crops from three regions, we show that simple colour augmentation recovers most of the accuracy lost when training data is scarce. As the journal publishes applied machine learning for agriculture, we believe its readers, especially those working with small regional datasets, will find this useful. The work is not under consideration elsewhere; a preprint is on arXiv (arXiv:XXXX). Data and code are openly available. The authors declare no competing interests."

Conferences

Most conferences don't use cover letters. Your abstract and introduction do that job, so make them clear.

RememberOne page: what it is, the finding, why this journal's readers need it, and the required statements.