[Koha] marc tag for keyword, Accession number

Dear Member, I have to convert text file into marc tag, I would like to know the exact marc tag equivalent for field "general keyword " so that it can be searched by following keyword in OPAC. I used 650$a for equivalent to keyword. But it was not showing in my OPAC. And Second, what should be the best tag equivalent to accession number in koha 3. Thanking You, With Regards, vijay kumar NCSI,IISc Bangalore