I am trying to build a prediction model using WEKA. For example, I plan to build a model for classifying whether something is leading to A or P using Database 1. I will then use another Testing and Training dataset to predict outcomes whether something is A or B using this model. Are there any prediction packages for that? I saw Forecasting packages but that is for numeric data. I am looking prediction packages that could help me classify data and make predictions. Also, can I save this model and make it publicly available so that others can use it as well and make similar predictions? Is this possible in WEKA?
Yes, of course you can make predictions with a model. Since it is not clear, whether you want to do that from the command-line, in the GUI or from code, I recommend you have a look at the following Weka wiki article:
https://waikato.github.io/weka-wiki/making_predictions/
If you want to use the API, check the articles listed here:
https://waikato.github.io/weka-wiki/using_the_api/
Also, every Weka installation comes with code examples, aptly named wekaexamples.zip.