There are a few schools and institutions in Israel which offer different Hebrew courses to international students and/or visitors. Among those institutions: Ulpan Kibbutzim that takes place in no less than 8 different kibbutzim in Israel, The Hebrew University, Levinsky College and more.
Each one of those institutions offers a different program which takes around 4-5 weeks (at least - can also be longer if you wish) so I've attached a link at the end of my message to an article about the different programs you can choose from and i advise you to contact 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.
Arabic courses are different - there are some institutes that offer long term courses that last between one semester and a full year. Among those institutes you can find the Hebrew University with a year long course, The Tel Aviv University, The Ben Gurion University and The University of Haifa that offer 4 weeks courses and more. If you want more information about the arabic courses please let me know and i'll attach an article about them as well.