Do bitcoin or crypto assets impact the total supply of money in a country?
They must do in practical terms, just as the use of foreign currency does
However, though not an economist, I suspect economists most often report on the money supply of a single government-mandated currency. This would be a question for an economics stack exchange website if one exists.
accepted as legal tender currencies in India by RBI.
Not so far as I can see
https://www.rbi.org.in/commonman/English/Scripts/PressReleases.aspx?Id=2152
The Reserve Bank of India advises that it has not given any licence / authorisation to any entity / company to operate such schemes or deal with Bitcoin or any virtual currency. As such, any user, holder, investor, trader, etc. dealing with Virtual Currencies will be doing so at their own risk.
Legal tender
The phrase “legal tender” has a special meaning, at least in jurisdictions following the UK model – it determines what forms of payment can be legally used in settlement of a debt. A shopkeeper can refuse legal tender offered for payment for goods or services where there is no established debt.
