I don’t think so. because it is a text field for a standard email protocol that AFAIK only allows text characters, and is displayed by practically every email client as text (not layout) information.
@elbanditoroso I tested it with just </bold> it didn’t work. I tried it with This is a test</bold> When I went to Sent file it was in bold until I clicked on the email.
…By the way I sent it to myself (the same email address) Anyway thanks for the response.
Why is it a problem for Gmail to allow the subject bar to be not different fron the body re. formatting?