Is there a possibility to attach files by default?

For example, when I send out an estimate, I would really like to send along my general terms and conditions. 

I can do that now by attaching the file manually, but it would be great if I could set Zoho up to do this for me.

From a legal perspective it is important that my clients receive the terms before we start working for them.

Hope to hear from you soon,

Best regards,

Menno