When creating or viewing a letter within a patient's chart, you have the ability to send a signed copy of that letter. You can do this by selecting the "Signed PDF" button found at the bottom of the page. Note: this will only work if you are a physician, or if you are an administrator creating a letter from a signed Encounter.
Clicking this button will prompt you to apply a Cover letter or select a location. From here, a PDF document of the letter will be generated with your signature and timestamp found at the bottom.
Please read the following article in regards to configuring your signature.