turbojet...turbofan

just wondering, what is the difference between the two of them and why did people say that turbo fan is better

A turbofan is a cross between a turbojet and Turboprop engine.

its more efficent at lower speeds

a turbo jet works on jet thrust alone where the turbo fan is a turbo jet with a large fan blade on in front
turbo fans are quieter and more fuel efficient but the turbo jet is better for very high speed