Here is an example specifying all available options (including minconf and fee). See more here: z_sendmany - Zcash 4.5.1-1 RPC Docs
zcash-cli z_sendmany "zs1examplea4lqxrtmlpkayj0hxpfdd3ve62xhd7jds8c2a8tqz5kekplt469eza5wu8djdvpauezv" "[{\"address\": \"zs1examplea4lqxrtmlpkayj0hxpfdd3ve62xhd7jds8c2a8tqz5kekplt469eza5wu8djdvpauezv \", \"memo\": \"Optional memo\", \"amount\": 1}]" 1 0.0001