Okay, if your question is “Can I build this ?”, Then the answer is yes.
You could train an SVM model to predict the characters based on it’s properties (There may be other models, check them out!). As for the question “Can I use a file from paint ?”, If you are ready to spend a lot of time drawing random images of all characters, then yes, you can. Rather than doing that, check for any publicly available character datasets, similar to MNIST. And then train the model using that rather, than building your own dataset on paint.
solved specific character recognition with machine learning [closed]