If there is a paper that says 'masjid' on it, is it permissible to sit on it? Also, if there is a car that has written 'Sunnah' or 'karama' on it, and then when people sit in this car, these phases/writing may be at a lower level than the feet, is that wrong? I am not making things up; I am giving examples of situations which I have faced, so please give a detailed answer.

All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallaahu ʻalayhi wa sallam, is His slave and Messenger.

What should be done is to respect what is written in Arabic letters and not expose it to disrespect. Whatever is considered disrespect of the Arabic words should be avoided. As for what does not constitute disrespect, such as the second situation mentioned in the question, then there is nothing wrong with it.

Allah knows best.