Launch the Lighting window 
from the sidebar and click 
to create a new spotlight.
The created spotlight will appear in the viewport one unit in front of the camera and point along the negative z-axis. You can use manipulators to move and rotate them around.
- Range defines the illuminated distance from the viewpoint of the light source.
- Color enables you to set the color of the light.
- Intensity sets the strength of the light.
- Spot angle determines the area directly illuminated by the light source.
- Penumbra angle defines the partially illuminated outer area.
- Shadow type lets you choose between soft, hard, and no shadows. Hard shadows have sharp edges and are fast to compute. Soft shadows are more realistic but may take longer to compute.
- Strength determines the darkness of shadows ranging from 0 to 1, with 1 being the darkest.
- Near plane sets the distance from the light source beyond which objects cast a shadow.
- Bias can be increased to counteract visual artifacts. Avoid increasing it too much, as it can cause the shadow to appear disconnected from the object.
- Resolution of shadows is set to medium for point and spotlights and to very high for directional lights. Adjust as necessary to produce high-resolution shadows.
Finally, compute shadows from the Lighting tool. Remember that shadows need to be re-computed if you transform the light source.