Setting the default signature in outlook for all of your users is a straight forward process but can also be challenging, depending on what you actually want to achieve.
- end-user should not be able to change the signature on his / her own
There is one possibility to use the group policy in order to configure the reply- and new message signature. This is the easy way.
It will prevent the users from changing those settings afterwards though. The fields will be grayed out in the outlook client.
- end-user should be able to make adjustments
This is the tricky part. There might be scenarios where you just want to provide an initial signature / default settings on the clients and allow the users to change.
Then you cannot use the group policy but need to set the signature in the mapi profile. Therefore the usage of the extended mapi interface is required. We created a utility (exe) to set the reply and new message signature name in outlook. Check it out here