It can enhance text or make it stand out a bit. You may want to do it for important headings for example. If you are designing a poster or a sign, you might have some or all of the text with borders and/or shading. There are lots of situations where it can be useful.
Adding black to a color is called shading.
shading
Lino drawing, is drawing without shading or adding tone to your drawings.
Adding black makes the original color darker. The hue of the color depends on the color that the black was added to.
Adding black to a color is called shading or darkening the color. It creates a darker or more subdued version of the original color.
Adding black to a color will create a darker version of the color.
The purpose is to make it sweet.
Dynamic shading can be implemented by using software or materials that adjust the intensity or direction of light in real-time. This can create depth, texture, and visual interest in a design by adding movement and changing shadows.
There are not much purpose of that.
The answer is white. However, yellow might be added to a color as well to make it lighter, but it might change the original color. Also, when you add white to a color it is called "tinting" the color. When you make a color darker by adding black, it is called "shading". Shading is also a technique in drawing. Be careful not to try shading and tinting because the result is the color is "grayed", by adding black and then white you cannot reverse the effects of the black, only change the effect. I hope this helped!!
Removes the colouration.
Borders can make important data stand out. You could (for example) use borders when creating something like a 'pro-forma' invoice - to help a person manually complete the form.