Herewith is a formal word meaning “with this” or “by means of this.” It appears mostly in official letters, legal documents, and business writing. When someone writes “I am sending herewith the signed contract,” they mean “I am sending the signed contract along with this letter.”

You might see herewith in a letter from a lawyer, a formal report, or an old-fashioned business communication. For example: “Enclosed herewith you will find the requested documents.” In everyday speech, people would simply say “Here are the documents you asked for” or “I'm attaching the documents.”

The word feels stiff and outdated in casual conversation. If you wrote to a friend, “I send you herewith my birthday party invitation,” they might wonder if you're joking or practicing for a role in a historical play. But in formal contexts, especially legal or diplomatic settings, herewith still appears regularly. It's one of those words that signals serious, official business rather than friendly communication.