How to Make Linux Run from a USB Drive

I've long heard of the great reputation of Linux, but unfortunately, the hard drive on my laptop is too small, leaving no extra space to partition for installing Linux. A while ago, after studying and experimenting on the original forum, I successfully installed Puppy Linux on a USB drive. However, this is a simplified mini version of Linux with very limited functionality. After a period of dedicated research, I have finally managed to install Ubuntu on a USB drive, which makes me very happy.