Tobit (if the values of dependent variable ranges between -6.96296 + 18.89634 what should be command in STATA for Tobit be..

tobit sav_index for_remitt_hh DRatio i.Locality_hh i.sex_hh i.age_group_hh i.edu_hh i.eco_activity_hh i.married_hh i.hhsize i.religion_hh i.District_Code i.land_acresnew , ll(-1)..is the above command right.

I would like to know more details on Heckman selection model which could be opted instead of the above tobit.
what are its command on STATA and what do we opt for it instead of tobit. I ran a tobit as my expenditure values concentrated between 0 and 1 .. so created an index so a negative value came into picture.. (-6.96296 + 18.89634.. this is the range )

please clarify .