If your website isn't showing up on Google or being mentioned ChatGPT, do this before you spend any time or money on SEO.
Search engines have an index where they store all of the data on the pages they show in their search results. And if your pages aren't in this index, they're never gonna show up on Google, ChatGPT, or any other search engine.
First, you're gonna enter this on Google and Bing to check that your website is actually being indexed. If any pages are missing from these lists, then you need to go to Google Search Console and Bing Webmaster Tools. They both work in exactly the same way.
So click on pages and then scroll down to find the ones that haven't been indexed, and they're gonna give you a reason why for each page.
I go into this index in my course, SEO Clinic. Because for some of these you just need to click request indexing. There's nothing to actually fix first.
But for others, there are issues that you're gonna need to address before you can get them indexed.
Let me know what you found in the comments.