Hi,
The signature files for Outlook 2010 and Outlook 2013 are saved in this location:
C:\Users\%username%\AppData\Roaming\Microsoft\Signatures
As long as the signature files are available there, the users are able to find the signatures in Outlook.
However, the signature files don't control when to use the signature, for "New messages" or "Replies/forwards". This is actually controlled by the registry:
HKEY_CURRENT_USER\Software\Microsoft\Office\x.0\Common\MailSettings
or
HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\x.0\Common\MailSettings
Name: NewSignature
Type: REG_EXPAND_SZ
Value: The name of signature to use for new messages
Name: ReplySignature
Type: REG_EXPAND_SZ
Value: The name of signature to use for reply messages
As each user may use different signature names, it may be hard to manage this for all of them.
For more details, you can refer to this kb below:
https://support.microsoft.com/en-us/kb/2691977
I hope it's helpful to you.
Regards,
Melon Chen
TechNet Community Su