You would want to bounce the light from the flash onto the subject like ceilings, walls, or other objects to get a better result.
If it is external then yes
flash synchronization or flash sync is the synchronizing the firing of a photographic flash with the opening of the shutter admitting light to photographic film or electronic image sensor.
Evaluative through the lens
Black bands
the difference is that a diffuser for camera flash is typically smaller than regular light modifiers. Since it’s portable you would be able to take it anywhere.
In photography a slave is a flash unit set to slave mode which will fire when it detects the output of another flash unit.
Use the exposure compensation setting on your camera to correct for under or over exposure.