RGBA stands for Red, Green, Blue, and Alpha. It is often used in web design to create a solid color with transparency. It is the most common format for adding color to elements on a website. RGBA always requires four values: a hexadecimal value for red, green, and blue and then the opacity, or alpha value which is a decimal between 0 and 1.
Hex color format is a six-character representation of a color. It consists of three pairs of two-digit hexadecimal numbers that represent the red, green, and blue components respectively. For example, the RGB values for white are #FFFFFF - this is known as hex triplet notation.