Claim HRA when not mentioned in Form 16

Hello friends,

I have to file ITR for AY 2020-21. I have not shown rent payment to my organization but now I want to claim it (I live in a metro city) while filing the ITR (I am a regular salaried person with no other income). I have rent agreement as well. How can I do it ? Can some one please provide steps or is there any documentation ?

Thanks,

AnksD