First, go to settings on your Wix website.
From the drop-down list of Settings go to Tracking and Analytics section. Please note that your website is published for you to access this feature.
On clicking the button you will see an option at the top right, +New Tool.
Clicking on that will give you a drop-down list, you can choose which type of code needs to be installed. Click on the appropriate type of code you are installing.
It is not be noted that for accessing any of these options, you need to upgrade your account first.
Choose Custom and select the page you want to add the code to. Place the code between the body tags and click Apply. This will make the code verified and the cookie banner to appear on your website.