An RFP template can be used to create RFPs in short-order. An RFP template is a collection of sections. So you will want to create these re-usable sections first.
Both RFP templates and sections are created and then available in the Library.
But, if you write an RFP and want to save it as a template, you can do that as well. In the details page of your RFP, check out the right-hand side where you can save the entire RFP as a template in the Library.
If you would like to use a template you have already created when drafting a new RFP Section, simply click on Add Section in the lower left-hand corner of your RFP, then this page will come up. Select the Use from Library tab at the top and Add Sections at the lower left-hand corner of the page.