How to create a template of a page or post?

Hello!

I have my portfolio with post in it. I want to create like a template or something to modify all at once in case in need. For example:

I create a post in Portofolio. I put like this:

Title
Image
Suscribe
Text box

After that I clone that post, and create 200 hundres post similar in portfolio.

But then, I want to change something on the order, or eliminate some things in the content:

Title
Text box
Image

How can reemplace the 200 hundred posts? How can I create a template of my content post named "portfolio", I desing in there the content, and after that i create the new portfolio post calling the template, in order if something is changed in the future, change all the post did it with template.

I hope you understand me! Thanks!

Best.
Sebastian.