To set a default signature for a specified email account in Outlook, please do as follows:

1. In the Mail view, please click Home > New Email to create a new email.

2. In the new Message window, please click Insert > Signature > Signatures.

3. Now the Signatures and Stationery dialog box pops out. In the Choose default signature section:
(1) Select the specified email account you will set the default signature for from the E-mail account drop down list;
(2) Select the default signature for all new emails from the New Messages drop down list;
(3) Select the default signature for all replying/forwarding emails from the Replies/forwards drop down list. See screenshot:

4. Click the OK button to close the dialog box. And then close the new email without saving.

So far, you have set the default signatures for the specified email account. From now on, the default signatures will be inserted automatically when creating, replying, and forwarding emails from the specified email account.

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