Hope you are doing good,
Yes you need to file GSTR 1 and GSTR 2.
Look GSTR 1 is for sale.
GSTR 1 needs to be filed even if there is no business activity (Nil Return) in the tax period.
And GSTR 2 is for purchase.
While filing the return of GST you have to put the detail of sale and purchase in GST portal.
Let me give you detail information in 3 case:
1) Suppose you don’t have sale and purchase in a month, then you have to file nil return in GST portal.
2) Suppose your sale is Rs200 and GST of sale is 20, Your purchase is 300 GST is 30, then you have to to file both return and then your ITC(input tax credit) is 10 and you don’t have to pay any taxes to govt.
3) Suppose your sale is Rs300 and GST of sale is 30, Your purchase is 200 GST is 20, then you have to to file both return and you have to pay to govt.10 Rs. GST.
Every businessman/women having GST must have to file GST return either having taxable income or not.