Several of my Yiddish classmates found the Yiddish keyboard offered by Lexilogos helpful. Essentially, the Yiddish alef-beys is laid out on the screen and you click on a letter to type it. Once you’re done, you can copy and paste what you’ve typed into a document or website. There’s also a link on the page to Lexilogos’s Yiddish dictionary. Here is the site: http://www.lexilogos.com/keyboard/yiddish.htm
If you know of other Yiddish keyboard websites or programs that haven’t been mentioned, please share them in this thread.