Templates are files that determine how a page functions. It consists of its style and layout and are built in the design manager by CMS developers, or you can download them pre-made from the HubSpot Asset Marketplace (mentioned and linked above).
Templates are slowly being phased out in favor of Themes. Themes allows marketers to build pages from scratch without a developer. The WYSIWYG style editor has a library of pre-set modules that you can drag and drop onto a page and customize with ease.
Modules are what make up traditional templates. They are blocks of content, such as an image, form, CTA, rich text, and a template will be made up of several modules or module groups. In Themes, modules are the building blocks that you drag and drop. The difference is that with Templates, you can only move modules in the back end (Design Tools). With Themes, you can move and edit modules on the front-end sans code.
Pages are your end game and what you publish to go live for the world to see.
The relationship between modules and templates is one-to-many, as the same module can be used several times across many different templates (these are called global modules). The relationship between templates and pages is also one-to-many, as the same template can be used to create dozens of different pages.
Global content is content you want to create once and then have remain the same across your website. Think of your logo and site header because they need to look the same across the entire website for consistency.
In addition, can make any module into a global module, or group of modules into a global group. Once you do this, you can no longer edit it from the content editors. For example, if you want to edit the copyright date in your website’s global footer, you can locate that module group in the design tools to make your change there.
This is an online directory of thousands of pre-made templates, themes, and modules that you can use to build a website in HubSpot.
This is a great resource if you don’t want to spend the money to build a custom website.
The marketplace provides access to assets created by hundreds of design agencies and freelancers, both free and paid. You can find blog templates, email templates, page templates, template bundles, and standalone modules.
With this said, if you don't have any design or developing skills, you may still need assistance for any customizations you want to do to the assets you buy. Or, if you want to convert your existing site to a Theme (so it looks the same as your existing page but allows you to build pages without devs) then you'll definitely want to bring in the experts.