Samsung smartphones, like all other Android smartphones out there, let you capture screenshots using the volume down and power buttons. Samsung also has gesture support for capturing screenshots – you can swipe the side of your palm on the screen from right to left to take a screenshot, in addition to the volume and power button combo.
Then there's the option to ask Bixby, Samsung's voice assistant, to take screenshots for you. But there's another method of capturing screenshots on modern Galaxy devices running Samsung One UI version 5.1 that you might not know: a toggle in the Quick Settings panel in the notification shade.
This toggle — called Take screenshot — is not visible in the Quick Settings panel by default. But that's easy to change. Simply swipe down from the top of the screen twice to access the Quick Settings panel, then swipe left until you reach the end and tap the + icon. Then, look for and tap and hold the Take screenshot toggle and drag it down from the upper half of the screen to the lower half, then hit Done.
Once you've done that, you will be able to tap the Take screenshot toggle by opening the Quick Settings panel at any time. However, keep in mind that since the toggle is accessed through the notification shade, you won't be able to use it to capture screenshots of the notification shade or of the Quick Settings panel and will have to use one of the other methods mentioned above.