Jobs at small Cincinnati companies nobody posts about - first time posting

A friend who works at a local manufacturer says there are openings not advertised online. It has been weighing on me all week. One is a print shop, one is an accounting firm and one is a clinic. What do you write in a cold email?

Keep everything in writing and save the confirmation numbers. It made the follow-up calls so much easier.

Visiting in person worked for a trades job. For office jobs, email was better.