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.
The correct vowel endings damma, kasra, fatha in Arabic can be a headache. If you are careless, you could turn verse 9:3 of the Qur'an into blasphemy (kufr).
There are many options for Arabic keyboards: hardware (qwerty and qwertz), mobile apps or virtual keyboards online. Here is a list of the best Arabic keyboards.