being from kerala does not affect your chances to get into delhi university however for best colleges under du you need to recquire very high percentage or equivalent percentage (if result is in cgpa)
Delhi university is one of the most reputed colleges in india .the admissions are merit based so yes! you need only 12th marks alone
first you have to fill the DU general admission form and then wait for cutoff lists if your percentage satisfied the recuired criteria the you will have to vist that particular college
here are the list of best college under DU
https://www.jagranjosh.com/articles/top-10-delhi-university-colleges-you-must-target-to-get-in-this-year-1492424100-1
also
https://www.collegedekho.com/articles/top-25-du-colleges-nirf-ranking-popular-courses-offered/
best of luck!
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