GST
GSTN has prepared an informative resource in the form of an e-invoice glossary and a step-by-step guide for your reference.
https://tutorial.gst.gov.in/downloads/news/pamphlet_e_invoicing_glossary_updated_17_08_2023_approved_final.pdf
INCOME TAX
A Handbook of Advance Rulings can be accessed @ [https://incometaxindia.gov.in/pages/international taxation/advance-ruling.aspx].