Welcome to the Board!
This is totally doable. What I've done in the past with something like this is to use a template concept, but also have a living document.
For example you can create your Estimate template & Summary sheet, then use VBA (Visual Basic for Applications) to transfer a completed estimate's data to the summary sheet, print it out & create a stand alone workbook, then clear the template and be ready to start again. That's actually the relatively easy part (and we can help you with it).
The hard part is making sure that your estimate template design is exactly what you want before you start writing code for it. As a beginner, you'll probably be explicitly referring to cells (i.e. Customer Name = A1) and if you decide to move it at some point in time you'll wonder why your code failed.
If you'll detail what ranges from the Estimate sheet you want to go to the Summary sheet someone can whip up the code for you.
Hope that helps,
If you PM me your e-mail address I'll send you an Updating Invoice example.