In simple words
Simha is the Vedic name for the sign Leo. It is ruled by Sun and is fixed (steady).
If your Moon was in Simha, read "As your Moon sign". If Simha was rising when you were born, read "As your lagna". Your chart page in Vedic mode shows both.
As your Moon sign
With the Moon in Simha, you feel with pride and warmth. You need respect and appreciation, and you give generous loyalty in return. Your emotions are strong and steady, and you dislike anything mean or small.
As your lagna (rising sign)
With Simha rising, you carry natural authority and a warm presence. People look to you for leadership. Humility and generosity make your strength easy for others to accept.
Growing with Simha
Lead by lifting others. Your light grows when it is shared.
Vedic signs are measured from the stars (the sidereal zodiac), about 24° behind the Western ones. That is why many people's Vedic sign is one sign earlier than their Western sign.