Can anyone help me understanding with hexadecimal color values?

Question

Hexadecimal color values

Answer 1

Hex colour values are in the form #RRGGBB where two consecutive digits, as a pair resemble the decimal values from 0 to 255.
So you define the intensity of the RGB channels in a scale from 0 to 255 for each to get a colour.
#FF0000 stands for the brightest red as the G and B channels have intensity values of 0 while red has max of 255 (i.e. FF)
Example:
Pink is full red and full blue, shades of purple are obtained when blue is at max and the value of red is approaching max. (i.e from #0000FF (pure blue) to #00FFFF(pink))

Answer 2

w3schools.com has an excellent color reference

https://www.w3schools.com/colors/