A:
Firstly:
We do not know any proof on the permissibility of differentiating between the grave of a woman and the grave of a man with a stone or suchlike and the basic ruling is that there is no need to distinguish between the two.
Secondly:
It is forbidden to
write on the grave whether the name of the buried person, (Part No. 9; Page No. 55) the date of his death or anything else because of what has been
related by
Al-Tirmidhy and
Al-Nasa'y
that the Prophet (peace be upon him) prohibited writing on graves...
The Sanad (chain of narration) of this Hadith is Sahih (authentic).