Most commonly, it is a sign that the cat is in pain or discomfort. You may want to take the cat to the vet to rule out any potential health problems.
It could also be a sign of stress or anxiety. Cats may experience stress or anxiety if there are major changes in their environment or routine. If you have recently moved or changed your cat's routine, it may be feeling stressed or anxious and as a result, lifting its tail up and meowing.
It could also be that the cat is trying to get your attention. Cats often lift their tails up and meow to let their owners know that they want something, such as food or water. They may also do this when they are bored and want to play.
If you are unsure of what your cat is trying to communicate, it is always best to take them to the vet to rule out any potential health issues.