Font Li Beirut has many alternates for both Latin and Arabic letters. To access them, you need slightly different methods for the 2 scripts because of the way Adobe’s text engines are coded.
For Latin, choose Adobe Paragraph Composer and you can then access the variants via the blue ribbon or the Glyphs palette. For Arabic, you can do the same, but the text direction will be left to right. If you choose the World-ready Paragraph Composer, you can type in the right direction, but the blue ribbon will not be active. There you can only use the Glyphs palette. See the video below for how to do this.
To access the variants in MS Word, you can type + after Latin letters to access their variants, and Arabic comma after the Arabic ones.