Sarah is having a hard time finding a template for her advertising business that she may be able to use at a later date and also make it available to her colleagues

Creating a custom template is the correct answer to this question.

Explanation:

Creates an existing template or document template

Following are the steps are given below:-

Firstly click on the File tab, and then click on the Fresh button. Then after that select the new from current under usable templates. At last click a template or a document similar to the one you'd like to make, then press Build Fresh.