Plateaus are very common, so don't get discouraged! Keep in mind that sometimes you just have to wait them out, as patience is key. Weight loss isn't always linear, so even if you have been stuck for a while, your weight may continue to decrease with time. Otherwise though if you continue to not notice any progress, it might be time to make some changes.
As you lose weight, your body starts to require fewer calories. This is why it becomes more difficult to lose weight as you get leaner. Sometimes, you just need to make small changes in your calorie balance to get back at it. Any weight loss you achieve will come from being in a calorie deficit – this means consuming slightly fewer calories than your body needs to maintain a stable weight. If you've lost weight already, your body may require fewer calories than before to stay at your new weight. You want to make small changes by either with removing a few calories from your diet, adding to your physical activity, or a combination of both.
Some practical and general examples of ways to reduce your calorie balance could be to focus on healthier or lower calorie dense food choices, cut down portion sizes a little bit, reduce snacking frequency, or increase days/length of exercise (or even just daily activity level). A small change or two can really add up over time.
Counting calories can be a great strategy to help get over your plateau as well. It is significantly easier to modify your food intake and exercise if you know how many calories you are eating and what foods are contributing these calories. You don't have to keep track of your caloric intake forever, but it may be helpful to give it a shot until you develop an intuition for your calorie balance.