Assuming you are working on a multi-class classification use case, you can pass the input to the model directly and check the logits, calculate the probabilities, or the predictions:
model.eval()
logits = model(data)
probs = F.softmax(logits, dim=1) # assuming logits has the shape [batch_size, nb_classes]
preds = torch.argmax(logits, dim=1)