We don’t have any caste system in Islam. People’s characters and merits are determined by their piety.
Some people are unfortunately inflicted by Hindu ideas and try to introduce this into our community by saying things such as a Sayeda or alawiyah woman, can only marry a Sayed. We also have those who refuse to let their daughters marry people from the opposite race: sometimes a person is of the same race yet it still isn’t enough as they are not from their city or village!
None of this is from Islam.
“O mankind! We have created you from a male and a female, and made you into nations and tribes, that you may know one another. Verily, the most honourable of you with Allah is the one who has At-Taqwa(piety)” (49:13)
May Allah grant you success
There are no castes in Islam. Q: 49:13 says:
O mankind! Indeed We created you from a male and a female, and made you nations and tribes that you may identify yourselves with one another. Indeed the noblest of you in the sight of Allah is the most God wary among you. Indeed Allah is all-knowing, all-aware.