There are a few Universities & institutions in Israel which offer different Hebrew courses to international students and/or visitors. Among those institutions: The Hebrew University, Levinsky College, Haifa University, and more.
Each one of those institutions offers a different program which takes around 4-5 weeks. I've attached a link at the end of my message to an article about the different programs you can choose from. I highly recommend contacting those that are relevant to you directly to get all the information you need about the admission, fees, and any other information you may need.