If the land to be gifted is ancestral then it is better to register Relinquishment deed in favour of your wife by your brother-in-law (sala) and if it is self acquired even then a court decree can be obtained. Gift deed is last option as it requires stamp duty. Anyway, your query is confined to gift-deed so your brother-in-law shall have to approach local deed-writer and shall have to get the deed drafted and then it shall be registered with registrar in the presence of your wife and witnesses. After registrarion, it shall have to be go enered in the relevant revenue record.
When your wife shall sell such properrty then the consequences of taxation shall have to been according to options/desire of further investment.