To edit any of the email templates that are sent from the system you must have company level administrator access.
To edit global email templates that would apply to all companies, you will require domain level admin access.
Company Level
Navigate to the Company in which you are amended the templates for, once you select the relevant company you will see 'Email Templates' on the right hand side of the page.
Once open you are then able to read through the titles and descriptions of each template to determine which one it is - if not all you are wanting to amend.
Once you are in the edit screen you are able to amend the subject, hover over any text field and select the pencil to edit the body of the email and save each time you have completed a template.
Domain level
To make changes to email templates that would apply to all companies, navigate to Administration > Email/SMS Templates.
Click 'edit' on the right, and make the necessary changes. Once saved, it will apply to all companies, unless custom changes on the company level aremade.