I need help to describe the color pink in an essay.

You do not specify whether pink is the subject of your essay or if your description constitutes just a segment of a longer essay on another topic. My attempt below considers the alternatives:
If pink is the subject of your entire essay:
Your essay should obviously commence with a thesis statement in which you divulge what the main theme of your paper is and what you wish to convey about the colour in your writing. The statement should be specific so that your audience is aware of the direction your essay will take. You could, for example write, 'We live in a world rich in color, but some colors are more significant than others. The color pink is a perfect example of such significance. It has, throughout history, retained its allure and is symbolic of the good, the bad, the mysterious, the mundane, the extraordinary, the practical and the metaphysical.'
Each following paragraph in your essay can then describe and discuss the color within the themes / main ideas you specified in your thesis statement. Your second paragraph may, for instance, provide a visual image of what pink looks like and what defines its allure. Your audience should be able to see the image in their minds since the descriptors you use convey the color as you see it. In this regard, you may depict it as 'pale red' or  'a bit of red tainted with massive dollops of white mixed in,' or 'oodles of white with just a tint of red blended in.' Whichever descriptors you use should be effective and enable the reader to see what you want them to see—your vision of pink. 
In each consecutive paragraph you can discuss the different symbolic associations and meanings pink conveys. Each paragraph would obviously deal with a different perspective. The conclusion of your essay should tie in with the introductory paragraph and convey a sense of completeness.
If the description is part of a longer essay on a different topic:
In this regard, your task should be somewhat easier. In this instance all you need to do is to use descriptors similar to the ones I've used in the second paragraph to describe it. If you need a more lengthy piece as part of an essay with a different theme, you could describe the color by mentioning its appeal to the senses. How would pink look, taste, smell, sound, or feel and what kind of emotion or mood would it convey? If someone should, for example, say, 'I feel pink today,' what kind of image would that evoke? Or imagine someone speaking of a 'pink sound.' Would it be harsh and jarring or soft and soothing? This approach can obviously also be used if pink should be the topic of your entire paper.
There are many variables you can choose from, but whatever you attempt, be creative! I have listed a number of websites you can visit for help and ideas. All the best!
https://en.wikipedia.org/wiki/Pink

https://www.bourncreative.com/meaning-of-the-color-pink/