Commonly referred to as Synastry reports
or Kuta and Kuja Dosha in Jyotish.
As you can see from the chart below theres a lot of energy that gets mapped between two charts in an astrological reading.
A reading can show the relationship of each charts
Moon, revealing their emotional connection.
Venus connection reveals love and relating,
Mars, the vitality,
Saturn, brings karma or lessons, connection thru time and challenges,
Jupiter connections are opportunity and grace and protection,
Mercury reveals communications.
Connections of these planets and Transits effecting these areas offer tell tale signs about your compatibility with another person.
It can also show timing of events between the two people.
These are discussed and layered with what each individual chart holds as well.
You can gain a better understanding of each other, not only how your charts work together, but also how your charts are working alone.
Current transits can bring fortune or challenge to a relationship.
See whats up in your relationship in the future transits as well.