22 September 2021
You can file ITR for AY 2020-21, u/s. 119(2)(b) of IT act, provided you have any refund claim. For that you have get permission from Jurisdictional ITO, to condone the delay in filling the return.
23 September 2021
Sorry, not possible, unless you get any notice from ITD in this regard. In regular course. you missed the last chance as on 31.05.2021.