You will need to use appropriate mark-up language or an appropriate authoring tool that can save it all in HTML. The added bonus is that you can get some credits in web design as well with 25657 or 25658. Wordpress allows you to export to HTML so if you aren't so great at coding than that might be the way to achieve this.
For the Folio board they are looking for the aesthetic - how it looks.
There are a lot of free software so go with whatever one you are familiar with. Or if you aren't familiar with any then I recommend Wordpress.
But make sure the site is designed appropriately.
This Youtuber has a series that goes over the different aspects of planning and designing a website. You should watch the others in this series as well. She recently moved to NZ so is aware of some of the limitations.
You should include some of the planning aspects on your Folio board. This is to show how you developed ideas from one point to another. For the standards around web design, you will need to include all the planning as well.