How to embed a Fillable PDF on a website

Hi I am using a Web Site Builder called 123-reg.com which allows to add Code in the Site Builder, and l wanted to embed a Fillable PDF that I have created for my clients to find online, so to fill the Form straight away from the site (without having to Donwload the PDF etc) .  My aim is to have the Fillable PDF visible on the site as if it's blended seamlessly with the site, as one...

However l have no idea about coding and l don't know what is the process to embed it in the 123-reg.com's Web Site Builder.

Do anyone know how to do this?  Thank you very much in advance for your very kind help.

Andrea