Google Indexing API in Opencart

Question

I wanted to integrate Google Indexing API on my E-Commerce Site for Better indexing. It's my first experience working on Opencart. I have worked on WordPress before. In WordPress, we can add the Service account JSON key in the Rank math plugin and it will start working. But In Opencart, where I should add that JSON Key because there is not any Rank math or an Extension like that? You can check my site. My Website URL is: https://wearglam.com/