when we want to see someone, do we say, I will drop off/by to ur home later in the evening...& also for a short note on email do we say. drope me a line(any preposition comes with it?) Thank u so much

I will drop off by your home later in the evening.

This is quite colloquial. It has a connotation of 'visit quickly'.

Drop me a line.

This is fine. No prepositions required.