Mitsubishi Outlander PHEV uses a GKN 'multi-mode dedicated hybrid' transmission with some notable differences than a standard auto gearbox.
Some Lexus & Toyota hybrids and PHEVs use the eCVT transmission, which uses 2-3 electric motors inside to adjust torque rather than a belt.
The Subaru Crosstrek PHEV (internationally also called the e-boxer platform for the Forester hybrid) uses a Toyota eCVT variant that also still facilitates symmetrical AWD instead of a separate electrical motor driving the rear axle.
As I said, there are exceptions, but broadly its just slap motors on output shafts. The motor is usually designed to bolt onto an existing automatic transmission housing.
Some Lexus & Toyota hybrids and PHEVs use the eCVT transmission, which uses 2-3 electric motors inside to adjust torque rather than a belt.
The Subaru Crosstrek PHEV (internationally also called the e-boxer platform for the Forester hybrid) uses a Toyota eCVT variant that also still facilitates symmetrical AWD instead of a separate electrical motor driving the rear axle.