How to change the content of the automatic emails

Where and how can I change the content of the automatic emails so that they only have two lines with a text like:
thank you for your order blablablba

regards blablablab

?

thanks in advance

EDIT: how to change the word "standard" on the automatic email that is sent, I cant find it in the files nor in the translation files

thanks in advance

Hi,
Can you tell me exactly what is your "standard" word ? is it a product name ? variant ? a shipping method service ?

sorry i forgot to add it, it is says standard in the automatic emails sent after an order is made see attachment, I looked in the email files as well as the translational files but I could not find where this standard comes from