Yes, you can connect an external monitor to the HP 255 G10 notebook, but there are some limitations and recommendations to consider:

- HDMI connection: You can connect the external monitor directly via the notebook's HDMI port.
- USB to HDMI adapter: If you want to use two external monitors, you can use a DisplayLink certified USB-A to HDMI adapter. However, the notebook's USB-C port does not support Alt-Mode or Power Delivery, so it cannot be used to connect to an external monitor.

It is important that you use the correct adapters and cables to ensure a stable connection.