The easy way would be to buy a battery-operated cam such as this one:

https://www.amazon.com/Tapo-home-security-camera-system/dp/B0BKZK4JGK

Arlo and others make similar models both more expensive and cheaper.

Most of the Indoor Cameras from both Kasa and Tapo require a wired connection unless otherwise indicated as a battery or wire free

I would recommend taking a look at the C420 series of Tapo cameras, as these may be powered by either battery or over a wired connection.