There are two parts of an affiliate sign-up form: the sidebar (the left side with a smaller width) is for your brand name and the program's sub-main heading; the main bar (the right side) which contains your brand logo, the program's main heading, details, and fields.
To hide the sidebar, follow these steps:
1. Go to Settings > Registration form
2. Click the Custom CSS tab and add the following code:
.basicSidebar {
display: none;
}
3. Click Save Changes to update the form.
Then the Affiliate registration form would look like this:
