What is the most appropriate method to prepare a sample of cheek cells for PCR?

Extraction of genomic DNA

Explanation:

Resuspend the cells (any number), smaller numbers also work, in 10-20 ul of TE buffer or milli Q water. boil for 5-10 min in a waterbath, quick chill, short spin. use the supernatant as a template for PCR.

If cells are very less, u can directly add cells to the PCR reaction without enzyme, boil for 5-10 min in a waterbath, let it cool slowly, short spin. Add enzyme to the supernatant and start the reaction at extension step followed by normal PCR reaction steps.