# Page Not Found

The URL `files/a8YA456hyzgsWOVPEmF3` does not exist. This page may have been moved, renamed, or deleted.

## Suggested Pages

You may be looking for one of the following:
- [Cập nhật chữ ký số lên thuế](https://huongdan.hotrokekhai.com/huong-dan-to-khai-01/cap-nhat-chu-ky-so-len-thue.md)
- [Thay thế hóa đơn](https://huongdan.hotrokekhai.com/xu-ly-hoa-don-sai-sot/thay-the-hoa-don.md)
- [Lỗi ký số](https://huongdan.hotrokekhai.com/mot-so-loi-thuong-gap-khi-su-dung-easyinvoice/loi-ky-so.md)
- [Đổi mật khẩu đăng nhập EasyInvoice](https://huongdan.hotrokekhai.com/mot-so-chuc-nang-easyinvoice/doi-mat-khau-dang-nhap-easyinvoice.md)
- [In và tải hàng loạt hóa đơn](https://huongdan.hotrokekhai.com/mot-so-chuc-nang-easyinvoice/in-va-tai-hang-loat-hoa-don.md)

## How to find the correct page

If the exact page cannot be found, you can still retrieve the information using the documentation query interface.

### Option 1 — Ask a question (recommended)

Perform an HTTP GET request on the documentation index with the `ask` parameter:

```
GET https://huongdan.hotrokekhai.com/huong-dan-to-khai-01/cap-nhat-chu-ky-so-len-thue.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

### Option 2 — Browse the documentation index

Full index: https://huongdan.hotrokekhai.com/sitemap.md

Use this to discover valid page paths or navigate the documentation structure.

### Option 3 — Retrieve the full documentation corpus

Full export: https://huongdan.hotrokekhai.com/llms-full.txt

Use this to access all content at once and perform your own parsing or retrieval. It will be more expensive.

## Tips for requesting documentation

Prefer `.md` URLs for structured content, append `.md` to URLs (e.g., `/huong-dan-to-khai-01/cap-nhat-chu-ky-so-len-thue.md`).

You may also use `Accept: text/markdown` header for content negotiation.