Which book should I read for NEET 2020? If it's conducted by NTA? If I study ncert or not because conductors are changed and I'm confused.

NCERT is must for NEET, no matter who conducts the exam.

List of books for NEET Preparation -

Physics -

Theory - SL Arora
MCQs - NEET Physics MCQs by DC Pandey

Chemistry -

Physical Chemistry -
NCERT + Balaji NEET Physical Chemistry MCQs + Previous year NEET/AIPMT Questions (2005-2018)

Inorganic Chemistry -
ONLY AND ONLY NCERT + Previous year NEET/AIPMT Questions (2010-2018)

Organic Chemistry -
NCERT (Must read all named reactions) + Cengage Organic Chemistry + NEET Organic Chemistry MCQs by MS Chouhan + Previous year NEET/AIPMT questions (2010-2018)

Biology -

Theory - NCERT
MCQs - NCERT Exemplar, MTG Fingertips

Previous Year NEET Questions + NEET Mock Papers -
Disha Publications