Most iPad models support AirPlay - and/or connection to a single external monitor using an appropriate HDMI Adapter. The most recent models of iPad Pro also support HDMI Alternate Mode/DisplayPort connections over USB-C. Compatible iPad models can be connected to a single monitor/TV.
You should note that iPad does not currently not support an extended-desktop view - as you may be accustomed with other computers, such as Windows PC - but instead permits the iPad display to be “mirrored” to a compatible external monitor/TV. When mirrored, the iPad’s screen aspect-ratio and relative scaling is preserved. An iPad can, however, “stream” media content directly to an attached monitor at the media’s native aspect ratio.
Connect iPad to a display with a cable - Apple Support
AirPlay system requirements - Apple Support
Apple has publicly announced a new feature for iPadOS16, known as Stage Manager, “with full external display support”. For supported models of iPad, you will be able to use an external monitor as a separate display. iPadOS16 will be released later this year.
Here is a link to Apple’s Press Announcement:
iPadOS 16 takes the versatility of iPad even further - Apple