Gst on licence fee of software

Dear Experts,

I am selling perceptual software to client example : Mr. A selling Software to Mr. B at INR 120000+GST, Both agreed on payment terms for 12 months i.e INR 10000+GST in 12 months.

Should Mr. A raise single invoice of INR 120000+GST and accept INR 10000+GST every month.

What about the 180 payment and input reversal in this case.