Sentinel 2 processing

Hi,I want to extract different vegetation index and biophysical variable from sentinel 2A-L1C and is it necessary to do preprocessing and how(steps to follow)?

Maybe you should do an atmospheric correction before the extracting the indices. You can use sen2cor or some other tool. This will probably improve the results. However if it is worth the effort depends on your application and the needed accuracy.
Instead of processing L1C to L2A your self, you can also download the standard L2A products from ESA.

Thank you marpet
Here is description of the image S2A_MSIL1C_20180127T075201_N0206_R135_T36PZQ_20180127T113410.SAFE
and I have tried to use sen2cor processor. my computer have 32 bit operating system and sen2cor is 64 bit,it unable to work because of operating system there sen2cor for 32 bit ?

I’m not aware of a 32Bit version.
The L2A data is not yet available for your region. But it should be available globally at Copernicus Open Access Hub soon.

ok marpet,thank you!
Let me try another option and I will inform you.