Creating word searches by hand, whilst possible, takes a lot of time. Also, once you've hidden all the words yourself, you'll probably remember where they are when it comes time to find them again. This is where the internet can help! If you search the internet you can find a number of useful resources which let you enter a list of words to create your own, personal game. I particularly like Word Search Party because it will spell check your words as you enter them, which helps catch those typos before you start hunting for the words! You are able to set the difficulty level to something you (or your intended audience) is happy with, and create a wonderful, personalized word search puzzle.
Another complicating factor is whether you download the file or a page, print a page, or sign up for an emailed download. All three work, but some form of file will be most flexible. Usually you have to pay for that.