Can ChatGPT-4 read documents?

Could you elaborate on the capability of ChatGPT-4 with regards to document reading? Specifically, is ChatGPT-4 equipped to analyze and comprehend textual content within various document formats, such as PDFs, Word documents, or even plain text files? Is there a limit to the complexity or length of documents it can handle? Furthermore, does it have the ability to extract key information or insights from these documents, or does it simply provide a surface-level understanding? Clarifying these points would help assess the practical applications of ChatGPT-4 in scenarios involving document processing and analysis.