The WHO Style Guide
WHO has an organization-wide Style Guide. The WHO Style Guide specifies conventions of spelling, punctuation, and the use of numbers and abbreviations; it offers direction on spelling of words with hyphens and accents, and acceptable spelling of foreign words and place names. The WHO Style Guide also lists the acceptable forms of address for dignitaries, country names and much more. We recommend that you familiarize yourself with the WHO Style Guide; find it on your Intranet.
Other guidelines apply to writing specific types of documents. For example, if your document will be going out under the signature of the DG or the RD, the required forms and protocols are very specific. These guidelines are well documented and are available from HQ.
Check with your own department for style guidelines; regional offices often have individual ones. Your regional style guide is available on your Intranet.