@Akash Levy could you please give suggestion or any reference about signal multiplier for changing the amplitude by giving 2 inputs one as DAC output and other PWM square waves.

Maybe you are looking for a level shifter?

With level shifter I guess it might be difficult to deal with various voltages 0.2,set voltage,reset voltage I guess transistors might not work due to that @Akash Levy

You said changing the amplitude, I thought you meant increasing the voltage. You can also use simple pass gate or pass transistor if you just want to pass through a smaller voltage than whatever Vdd you are using

ohh thank you so much i understood now

I’m not familiar with which transistors exist in the open-source analog PDK, but if I recall, there are core (1.8V) transistors and I/O (3.3V) transistors. Both of them can be used; the core ones will be smaller area but have higher pass gate resistance. The I/O ones will be larger area, but you will see very small pass gate resistance. It’s up to you which to use based on your design strategy/constraints. You need to make sure the voltages you use are correct

Thank you so much