In astrology, an empty house simply means that there is no specific planetary emphasis in that area of life. It doesn’t mean that the house’s themes are unimportant or inactive, just that they are not a primary focus for growth, challenges, or emphasis through planets. Every house is still influenced by its ruling sign and ruler (the planet that rules the sign on the cusp of that house).
Look at which zodiac sign is on the cusp (beginning) of the second house. Each sign has a ruling planet (e.g., Taurus is ruled by Venus, Gemini by Mercury, etc.), and that planet becomes the "ruler" of your second house. The qualities of the ruling sign give insight into how you approach finances, values, and material security.
For the sixth house, similar to the second house, when the sixth house is empty, check the ruling sign and where its ruling planet is in your chart. For instance, if Virgo is on the cusp of the sixth house, look at where Mercury is located and how it is aspected. The sixth house is about daily routines, work, and health. An empty sixth house may indicate that these areas are more "stable", or that they are not areas where major life lessons are likely to come from.