Once you've created a workflow, you can add automation by attaching email templates to steps in the workflow. If you use the SMS and Inbound Call Tracking addon, you can send automatic text messages in exactly the same way.
Attaching Email or SMS templates to a Workflow step
Go to one of the email or SMS steps in a given workflow and click on the paper clip icon to the right of the description.
You can search for and select a template that already exists or create a new one.
Set it to send Automatically
Select whether or not to send out the template automatically when the workflow task becomes due by checking the lightning icon (it will be colored blue if automatic, grey if manual; the step icon will also have a blue background color). If selected, the workflow step will be completed automatically once the email or text message is sent out.
The email will be sent out on behalf of the agent assigned to the lead when the workflow task comes due. Alternatively, you could assign it to a single user all the time even if the user isn't assigned to the lead. Read this article for more details. The assigned agent's email signature will automatically be appended to the end of the email template.
If an email workflow task that is set to auto-send is manually completed prior to the due date, the email will NOT be automatically sent out.
Manual Email Steps
If a workflow step has an email attached to it, but the auto-send (lightning icon) option is turned off, the workflow step will create a task that has the email template attached.
You can send this template to the lead by clicking on the task (from the lead's page or the Tasks page). This will open the email editor with the template already inserted and allow you to edit and send it from there.
If you want to edit the email template from the workflow page itself, simply click on the template chip, make any edits you want and click "Save".
Automatic Email Drip Campaigns
Email automation can be used to create email drip campaigns as well. Simply create a series of email or SMS steps in a workflow (following these instructions), attach templates to them, set them to send automatically and add a delay to each step.