I've noticed that Q# favors Little Endian. Meaning that most operations are designed for this type of encoding. Is is it the same with Qiskit?
Qiskit uses little-endian for both classical bit ordering and qubit ordering.
For classical bits:
A 3-bit classical register
creg with value
The ordering is with respect to the tensor-product structure of the state space. So a 3-qubit quantum register
qreg with wave-function $|\psi\rangle = |A\otimes B\otimes C\rangle = |ABC\rangle$ has
Similarly for representing unitary matrices of a circuit. $U = U_A \otimes U_B \otimes U_C = U_A U_B U_C$ would have $U_C$ acting on
qreg, $U_B$ acting on
qreg and $U_A$ acting on
Note that the bits are labelled from right to left. So cr is the one to the furthest right, and so on. As an example of this, here's an 8 qubit circuit with a Pauli X on only the qubit numbered 7, which has its output stored to the bit numbered 7.