Hello everyone

I'm trying to read data from incremental encoder using raspberry pi 3 B
currently using Qt Creator 4.8.2 Based on Qt 5.11.3 (GCC 8.3.0, 32 bit).
does anyone knows which IO Pins use full to capturing encoder signal and if any library which is compatible with raspberry pi and qt creator?
I hope my question is clear enough.

really appreciate if someone can help me
thanks in advance.