pls i need help on how to convert 240ac volt to 6dc volt.

 

Hello,

How much current is the load?

You can bring down the voltage with a transformer.
Rectify this lower voltage, buffer it with a capacitor.
A voltage regulator like a LM317 will stabelize it.

Bertus

 

This is the second such similar request from this OP. If the interest is to obtain the DC voltage without a transformer, that is not safe, nor will we discuss transformerless supplies in these forums.