Question 64:

I forgot to give detail of 1 sale bill in March 2018 return. Now what is way to show the same.

Answer  

If any sale bill is not feeded in GSTR-1, then you fill your invoice details in succeeding GSTR-1 with correct details of invoice (i.e date e.t.c.)
Thus you can fill your march invoice details in April month GSTR-1. Further the recipient can be able claim ITC in the month of march.
Please note succeeding month means any month comes after the month in which return is filed it does not mean next month only.  (reply dt. 06/02/2018)