Grammar is in everyone's everyday life. Using proper grammar is important. It shows that you know how to communicate well and people understand what you are saying.
Some employers will not hire someone who has poor grammar
Here is a quote of an employer who will not do so.
Kyle Wiens says, “I’ve found that people who make fewer mistakes on a grammar test also make fewer mistakes when they are doing something completely unrelated to writing—like stocking shelves or labeling parts.”