Templates in Gmail are emails that you can set up to use as starting points for new emails, or as just generic emails that you can send to people over and over again, without having to type the whole email out again by hand. Think of it in terms of mass-production factories: they often don't have time to sculpt every item that they make by hand, so they often use moulds to create a basic shape for whatever they're making, and then refine the products from there if they need to. Templates are like the moulds of email, in a way.
An example of when you might want to use this is if you're running a business and are currently looking to hire. You're probably going to have a large number of prospective candidates send you application packages, and you won't have time to send out dozens — perhaps even hundreds — of personalized responses. In this case, you might want to use a template to send a generic response that you can simply personalize by adding the person's name at the top.
To Create a Gmail Template
Go to www.gmail.com and log in (if you haven't already). When you get to your main "Inbox" screen, click the settings button () in the upper-right corner, and select Settings.
Click on Labs in the menu across the top. This is where the tech-savvy users of Gmail put up new ideas for features, and let people like you test them out. Scroll down the alphabetically-ordered list until you find a feature called "Canned Responses." Click the button beside "Enable" to enable this feature. (Also, you can ignore the note about it being for "truly lazy" people. We won't judge, we promise).
Now, scroll down to the bottom of the screen and click Save Changes.
Once you get back to your main "Inbox" screen, click Compose to bring up the composition window, as if you were going to write an email to somebody. Click in the main text box (highlighted below) and type in the message that you want to use as a template. Now, instead of sending it, click the button in the bottom-right corner of the composition window, move your mouse cursor over Canned Responses, and then click New Canned Response.
A new window will pop up asking you to name your template, so that you can tell it apart from your other ones. Type in whatever you want to call it, and then click OK. (Note: if you have already typed in a subject title for your email, it will be used as the name of your template by default. You can, of course, type a new name if you want to call your template something else).
Using and Managing Gmail Templates
Click Compose in the left-hand menu again to start a new email. Click the arrow icon () in the bottom-right corner of the composition window, and move your mouse cursor over Canned Responses. You will notice that, since you have at least one template now, you have some new options.
— Under "Insert": Click on the name of one of your templates to insert the message associated with that template into the main text box of your composition window. Presto! Email instantly written! Now just add recipients and a subject, and send it off!
— Under "Save": If you've already written an email, you can click on the name of one of your templates to save your message as that template. Be careful, as this will overwrite that template's previous message (but you will need to click on OK in a confirmation window that pops up, so you'll be able to cancel this if you have second thoughts or did it by accident). Or, click New Canned Response and follow step 5 above to save your message as a brand new template.
— Under "Delete": You can click the name of one of your templates to get rid of it, if you don't use it any more. You will have to click OK on a confirmation window that pops up, so you can cancel this if you have second thoughts or did it by accident.
And that's how you use templates in Gmail! Hopefully, they will save you some time when writing certain types of emails!