If you sign most of your emails the same way, you can easily specify a default signature to automatically insert into new email messages and replies and forwards. This can be done directly in the Signature editor in Outlook 2013.
You can create multiple signatures for each email account and define a different default signature for each account. When you change your sending account when composing a new email message, the signature would change automatically as well.
NOTE - To have a signature added automatically to new email messages and replies and forwards, you must have a default signature assigned in each email account. If you don’t want a signature in every account, you can create a signature with just a space, a full stop, dashes, or other generic characters.
To assign a default signature, open Outlook and click the File tab.
Click Options in the menu list on the left side of the Account Information screen.
On the Outlook Options dialog box, click Mail in the list of options on the left side of the dialog box.
On the Mail screen, click Signatures in the Compose messages section.
To change the default signature for an email account, select the account from the E-mail account drop-down list on the top, right side of the dialog box under Choose default signature. Then, select the signature you want to use by default for New messages and for Replies/forwards from the other two drop-down lists. Click OK to accept your changes and close the dialog box.
Click OK on the Outlook Options dialog box to close it.
You can also access the Signatures and Stationery dialog box from the Message window for new emails and drafts. Click New Email on the Home tab or double-click an email in the Drafts folder to access the Message window.
Click Signature in the Include section of the New Mail Message window and select Signatures from the drop-down menu.