LibreOffice - unlike Microsoft Word - does not offer to change the color of Arabic diacritical marks (tashkeel/harakat). However, there are two tricks.
Arabic keyboards lack many important special characters. Here is a list of the most important characters and signs which you can copy and paste.
Arabic is usually written without vowels (tashkeel). The website Forvo can help you to find the correct pronunciation of Arabic words and names.