thank you very much for such a quick response!!!
I hired a consulting firm and they suggest me to provide working emails samples (not just email address, but complete emails) that prove my job duties. and they make it sound very important to do so. But we are not allowed to use personal signatures when sending emails externally, so I couldn't find any to prove that it was me who wrote and sent those emails. and now I'm worried if it will make my case unpersuasive if I don't provide any.