When you have created a page inside your workspace that you want to use again, you can create a template out of it. This allows you to easily create new pages based on the template. You can keep the page templates to yourself or share it with your organization.
Once you are on the page that you wish to use as the base of the template, you can follow these steps:
Click on "Page menu (The three dots "..." next to Edit page button)
Click "Duplicate page"
Select "Create a new page template"
Review and edit the name of the page template (the original page name is used by default)
Click "Duplicate"
You will be taken to your new Page Template