Hi Rajesh, is this the command you ran?

plink --vcf myvcf.vcf --maf 0.05 --recode --out myplink

and did that command give you this error?

If it didn't work, you can use this tool https://watson.hgen.pitt.edu/docs/conversions/vcf_or_bcf_plink.html

Now coming to your question, if you are in need of a plink supported bcf or ped file, you have to first understand what a PED file contains.. it is basically pedigree/family information usually accompanied by a *.map file.  A much detailed and good explanation in simple English can be found here http://gatkforums.broadinstitute.org/gatk/discussion/7696/pedigree-ped-files

This is the tool you may want to use 

https://software.broadinstitute.org/gatk/gatkdocs/3.7-0/org_broadinstitute_gatk_tools_walkers_variantutils_VariantsToBinaryPed.php

And finally here is a crisp Biostars thread on the theory of how a map file and ped file should look like for a given CSV file - https://www.biostars.org/p/47060/

Good luck!

Thank you @Venkatesh Chellapp ,

But I did not get an exact solution to convert vcf file to plink format. Because in my VCF file GT field are missing. And I am unable to figure out how to calculate the GT field in vcf file.

Help me if you have suggestions.