You can embed a forum into your GoDaddy website by getting your forum embed code and then following these instructions to insert the embed code into your GoDaddy website:

Step 1: Get your embed code

1. Log in to your Website Toolbox account.
2. Click the Integrate link in the main menu.
3. Click the Embed link.
4. Click the Embed your forum link.
5. If a Create A Subdomain First button appears, click it to connect your forum to your website domain so that it remains embedded when accessed from the Safari browser, or click Get Embed Code to come back to this step later.
6. Click Get Embed Code and copy the embed code to your clipboard.

Step 2: Add the embed code to your website

Once you have the embed code, you can add it to your website by following the steps below.

1. Log in to your GoDaddy account.
2. In your Products list click Website Builder, and then click Manage next to the account you want to use.
3. Click Edit.
4. Click Pages.
5. Click Add.
6. For Page Title, enter Forum.
7. Click Create Page.
8. Click Add Section.
9. Click HTML.
10. Click the white box that appears.
11. Click Pages.
12. Click HTML.
13. Paste the embed code into the Custom Code text box.
14. Click Done.
15. Click Publish.
16. View your GoDaddy website. A Forum link will now appear in the navigation of your website. Clicking that will open a page with your forum embedded in it.

Here is a reference help article from GoDaddy with instructions related to adding HTML on your GoDaddy website.