o set up email templates navigate to Setup -> Email templates and change the content according to your needs.
You can set up a general email signature in Setup-> Settings-> Email, this signature will be used on all email representing your company.
All email templates will be sent from the general email that is configured in Setup->Settings->Email.
How multi-language for email templates is used?
Customer 1 have language English
Customer 2 have language Dutch
When an email template will be sent to Customer 1 the content will be taken from English email template, for staff Customer 2 the content will be taken from Dutch email template.
The same procedure is applied for staff members.
When sending email template to lead eq. proposal the system default language will be used.
What will happen if the content is empty for email template and user use this language?
In case the content for the template is empty for a specific language which is not the default system language the content from the email template will be taken from the default system language setup in Setup->Settings ->Localization. Make sure you always populate the default system language template.
The system will auto slide down the languages that are used over the system based on staff and customers when you navigate to edit specific email template.
Disabling email templates
Open email template and check the disabled field. If the disabled field is checked this email wont be sent ever.
Eq. If you want to disable sending welcome email when creating contact navigate to Setup->Email Templates and find the template with name: New Customer Added/Registered (Welcome Email) check the disabled checkbox and save.