Free webmail services, such as Google's Gmail, are just as good as using an email address from your ISP coupled with an email client such as Microsoft's Outlook. They ensure users can access the same functions, such as email forwarding and even the ability to add a signature to every message that's sent.. Here's how to set up a signature in Gmail.
Sign in to Gmail, then from the settings menu (depicted by the image of a cog) on the right-hand side choose Mail settings.
Scroll down to the section labelled signature and enter the text you want pasted on each email in the box. You can add basic formatting including changing the font, colour, alignment and even adding bullets or images.
Now check the box next to the signature text and press Save changes. Your signature will now be added to every email you send.