How do I find capacitor values?

[RubyWindow]

I'm figuring out how a circuit works where capacitors are used as simple low pass filters by connecting them to ground as seen in the picture. My question is, how do you calculate what capacitance is needed for the capacitor? Or can you just stick any low uf capacitor in and it would work? (sorry if the image doesn't work I'm still new to this)

[Mads Barnkob]

Here is a good article with a little background and an example of how to calculate decoupling capacitors: https://resources.altium.com/p/what-size-decoupling-capacitor-should-i-use-my-digital-ics

It prevents noise, by preventing a voltage drop, that would possibly result in high frequency resonance on the power bus, all the way from DC bulk capacitance to load. The decoupling capacitor sits locally and prevents the voltage drop from happening.