Hi,
You can add as many hyperlinks as you need in one email signature. However, one object, says an image, a piece of text can be added with one hyperlink.

Hi Nomfundo,
In the Signatures and Stationery dialog, you need to select the image first, then click the Hyperlink button, and finally add the linked to address. (See attached 01.png)

After creating or editing the signature. You can insert the signature in a new, replying, or forwarding email. In the message body, you should hold the Ctrl key and click the linked image simultaneously to open the specified webpage. (See attached 02.png)
By the way, if your recipients receive the email with linked image, they can directly click the image to open the webpage, without holding the Ctrl key.