I have a 5V DC submersible motor. I need to control( no speed control ,only ON/OFF) it by ESP32 microcontroller via a 5V RELAY CHANNEL. So if I need a N-CHANNEL MOSFET or a BJT to control the motor via a 5VRELAY MODULE along the ESP32??

 

Why do You need a "Relay-Module" ?
Just use a Solid-State-Relay.
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Yes, that or a relay. Tell us about the motor - how much current does it draw and what power supplies are available to drive it? Do you have any particular part in mind for driving the motor?

 

You can use a BJT, MOSFET or relay to actuate the motor. Make sure that whatever you use can handle the startup current of the motor and that you protect the switching device from the back EMF of the motor with a reverse diode connected across its terminals.