पढ़ना means -> to read सीखना means-> to learn.

Thank you, Alex!

An interesting addition to it's usage is namaz padhna: to read prayer, i.e. To Pray (for muslims). However, as a Hindi learner (non-native speaker) myself, I think I see where your question is coming from. I have seen padna (paRna) used where in English I would say "study". So it may be partially specific to how Hindi language characterizes 'study".

पढ़ना means to read something and सीखना means to learn something for example you are reading book. You are learning Hindi