Forces are balanced when they cancel out, so the resultant force on the object is zero. On a free body diagram the arrows pointing one way are equal in total to the arrows pointing the opposite way.
A book resting on a table is stationary. Its weight acts downwards and is balanced by an equal and opposite contact force from the table pushing upwards. A car travelling at a constant speed along a straight, level road has a driving force that is equal to the drag force, so the resultant force is zero. A parachutist falling at a steady speed has a weight balanced by air resistance, and has reached terminal velocity.
When the resultant force is zero, a stationary object stays stationary and a moving object keeps moving at a constant speed in a straight line. Balanced forces do not mean that the object has to be stationary, because it can still be moving with a constant velocity.
