Home security cameras used to be pretty tough to install. I remember knocking dozens of holes in my drywall to pull Cat 6 cable through my home so they can be connected to a local server. Nowadays the simplest way to monitor activity inside and outside of your domicile is to pop up a wireless camera. Many of these are small and have 4K capability with a microphone and speaker.
Wireless cameras do need to be charged every few months so you need to consider that when placing and mounting cameras around your home. Wired cameras are also available but need access to a power outlet or other source.
Here is a breakdown of different types of cameras for different needs. As seen on FOX 7 Austin.