Your boss has a significant affect on your success and happiness at work, so it's crucial that you know how to communicate with them. Some bosses make themselves available and are easy to communicate with. Other bosses are unapproachable, they either don't want to, or for some reason just don't have time to communicate with employees.
When I was a manager I used the method called "managing by walking around". With this method, the boss spends a lot of time walking around and chatting with employees. I would sit with each of my employees once or more each day and participate in small talk and jokes. This made my workers feel more comfortable with me and so they revealed things about themselves and problems they had with their assignments that more formal bosses never learned.
Many bosses don't have the luxury of managing by walking around. They are under a lot of pressure at work, maybe struggling with corporate politics, so they just don't have time to make themselves available to their workers outside standard department meetings. Some bosses have introverted personalities so they find it uncomfortable to communicate with people. But considering the impact of your boss on your success and happiness at work, it's important that you make an effort to communicate with them.
Some bosses like to involve them self in your assignment. Some bosses want to know every little detail of the progress on the assignment. I've seen cases where the boss gives an assignment, and then sits with the employee while they work on the assignment. Most of the time, boss involvement relates to making decisions. Some bosses want to make all the decisions, especially when the worker is new and unknown.
Some bosses expect you to make all the decisions yourself. They give you an assignment and then make them self scarce so you can't ask any questions. They just want you to get the job done. They don't want to be bothered with the details. You need to learn how to accommodate the work style of your boss.
The best policy is to make as many decisions as possible yourself. Keep your boss informed about the progress of your assignment with regular updates. Recognize when the importance of a decision requires you to consult with your boss. Respect your bosses time. If you need help, approach the boss at an opportune moment for the boss and ask when would be a good time to talk. Before you approach the boss for a decision, be prepared to offer possible solutions that the boss might choose from.
Some bosses are uncomfortable giving a worker feedback, especially if the feedback is negative. Without feedback you can't succeed at work. The solution is to ask your boss for feedback. The best time to approach a busy boss is early in the morning if they come in before working hours start, or late in the day if they stay after working hours end. Ask them how you could have done better on an assignment.
Sometimes the only way to communicate with your boss is through a company messaging application or email. But don't expect an immediate response. Some bosses plan their day to read and respond to their email first thing after they arrive at work. Some plan their day to read and respond to their email last thing at the end of the day.