I usually recommend that you open a blank document, then set that up with your necessary elements - font and size, margin settings, spacing, indents, etc.
Then, before typing anything, save that document to a place convenient for you.
Name the document "school template", or whatever helps you.
And, use that file whenever you need to make a school document.
You don't want to change or lose your template, so after creating your assignment, save it as a different name (maybe ref. the class and date, for example) - and you will always have that structured template available to use.
Make another template for different classes that may have other requirements.
(easy-peasy!

)