Understand why your cat may be hiding Recent changes at home? (new furniture, redecorating, moving home…) Visitors, new family member, new pet at home? Competition or tension with another cat? Cats need to hide when they are stressed so while dealing with the causes, make sure that You provide multiple cat hiding places (Cardboard boxes, baskets, open cupboards etc.) Cat Hiding places are always accessible to your cat (cats like to perch in high places) Respect your cat’s decision to hide and do not force them to come out. Get your cat checked by a vet: In some cases, underlying medical conditions can cause cats to be stressed and therefore hide (e.g. pain or dental issues)
Cats hiding can be completely normal. For cats anything out of the ordinary, unfamiliar, new or just not part of their everyday schedule is automatically (and naturally) perceived as a threat.
Have a vet check up, to check that there are not any medical issues or pain that is causing your cat to hide under the bed.
Maybe this is something not to worry about. They could also actually be sleeping; maybe your cat just likes that spot under your bed for some warmth, peace and quiet and finds it a nice safe place for a undisturbed snooze. 
However, this would mean that your cat doesn’t spend all their time there and when under the bed, they are relaxed and always sleeping there, so look out for their body language and any signs of stress or tension. Cats spend much of their day napping, so they may chose this private, comfy place to curl up to conserve body heat and hide themselves from potential threats. 
If something has changed or is new this perceived threat is not taken lightly (as they are natural prey animals) and they will hide, for example under your bed for safety until they realise that it is safe and this is not something that should be feared. Meaning your cat will come out after a while.
If your cat hides often or there hasn’t been any additions, visitors or changes to their schedule or environment. Then take your cat to the vet and try to comfort your cat at home and create the most comfortable calm environment as possible.
Cats can hide because they feel stressed and anxious. 
Do not scold, shout or swat or force your cat to move or do anything to control/correct them, this will make things worse. Cats will perceive this negative punishment as a threat and act fearfulling with avoidance or aggression. Do not forcibly remove your cat from her perceived safe area. They are in this area as it makes them feel safe and cats feel less stress when they are able to choose movement and are able to move freely. Lessening stress will likely decrease the cat’s hiding behavior.
As tempting as it can be, do not stroke or soothe your cat during the hiding. You may accidentally reinforce this with the praise and increase your cat’s want to hit. Instead, try to ignore the cat and give them space. 
Do praise your cat for bravery and for any other behavior you want more of.
Think of ways you might make it worthwhile for your cat to come out of hiding. Call your cat for meals and treats. If your cat will eat near you, try hand feeding your cat. Lack of appetite is one sign of stress. If the cat won’t take food from your hand, try sitting quietly near your cat and tossing an occasional treat. If your cat takes the treat, toss the treats closer to where you are sitting. Over time, the cat may take the treat from your hand.
If all of these suggestions fail to reduce your cat’s hiding behavior then make sure you visit with your cat frequently to give mental stimulation and ensure he or she is getting nutrition, water and access to the litter box. Or, consider giving your cat a private room that is people and pet free. Make that private room a cat sanctuary that has everything your cat needs for comfort and security.