I want to build project using 6 dc motors and 4 step motors. (All 5v) How can I do it with uno?
If I can't do it with uno what is solution for it?
And is there any motor shields for that?
I think you would need a Mega for that.
What stepper motor drivers are you proposing to use. The usual ones such as a Pololu A4988 need a step and direction connections to the Arduino - so 8 I/O pins for 4 motors.
The choice of driver for the DC motors will also determine the number of pins as will the question of whether you need speed control and forwards and backwards motion. You may need 2 PWM pins for every motor.
I am not aware of any motor shields that could meet your need - especially as stepper drivers are very different from DC motor drivers.
It would help if you post links to the datasheets for the motors you plan to use.
...R
Stepper Motor Basics