Attached in mail or attached to mail

A subtle distinction!

"Attached in mail" is not a common phrase, and it's likely that you meant to say "attached to mail" or "attached to a mail piece".

Here are a few possible meanings:

1. Attached to a mail piece: In this sense, "attached" refers to something being physically attached to a mail piece, such as a letter, envelope, or package. For example, a stamp might be attached to a letter.
2. Attached in a mail: This phrase is less common, but it could potentially refer to something being included or embedded within a mail piece, such as a document or attachment being sent via email.

To clarify, which meaning did you intend?