Gift to brother

A mere Self Declaration in a Letter form Confirming the Gift will enough.

Gift Deed is advisable.......

Any type of registartion is required for letter or gift deed like notary...

A Notarised Deed - Fine 

A gift deed is required to be registered in case of gifting immovable else a notarized deed will work.

Source:https://www.indiantaxupdates.com/2013/03/05/gift-deed-meaning-drafting-and-format-to-download/

Quick question

Will the receiver of gift become liable for tax?

thanks

Mayank

A simple deed will be sufficient as the amount of gift is not large and also in cheque. The amount received by Mr. B is tax-free.