Confused about product options

I’d like to build something that submits prompts containing a URL, and for the LLM to browse / download the site that I linked, but I can’t figure out which products, if any, support reaching external URLs. I’ve seen references to a “Browsing” function for ChatGPT Plus (to which I am subscribed), but I don’t seem to have access to it. Does anyone know which product(s) can access external URLs?