Let's show you how to emebed the form into any of the shopify website page by the theme editor using the Custom Liquid/Custom HTML section. For example, you can embed a pre-order form in your product page. 

1. Copy the form code.

2. Click Add section, select Custom Liquid(Custom HTML is the same)

3. Paste the form code you copy before. Click Save

For the other way, feel free to contact us for support directly.