There are different ways to add a quiz to Wix.

The simplest one is to add the quiz generator through wix. You can go here to overview the options.

But if you prefer to create the quiz using Google Forms, this is the way to embed a google form on wix.

Embedding a Google Form on a Web Page

Google Forms are a great way to gather information, and embedding Google Forms on a web page is easy.Instructions for creating Google forms are available.

1. First, go to the Google Form that you want to embed in Google Drive.
2. If you are in the spreadsheet view, click the Form drop-down menu at the top and choose Embed form in a webpage. If you are in form editing view, click the More Actions button at the top and choose Embed.
3. A dialogue box will pop up that contains the embed code. Copy that embed code.

4. Now open the page that you want to display your Form on in Dreamweaver. Put your cursor in the place where you want to embed the Form, and go to Code View. Paste in the embed code, as shown below:

9. Switch back to Design View. You won’t see the Form in Dreamweaver, but you will if you preview your page in a browser, as well as after you upload your page to the server and view it.

Subscribe to Changes on the Google Spreadsheet

For responses will be automatically inserted into a Google spreadsheet. Whomever created the form owns the spreadsheet. Like all Google items, both the form and spreadsheet can be shared.

To be notified when someone fills in your form, you need to subscribe to changes on the form:

1. Open the spreadsheet that collects the form responses in Google Drive.
2. Click the Tools drop-down menu and choose Notification Rules
   
3. Check the boxes for Notify Me … A User Submits the form, and Notify me with … Right Away
4. Click Save

Source