If your bitcoin stored in exchange then the only way to know if you are illegible is to contact support of that exchange and if they support the fork that time you will automically receive it in your exchange wallet that time no need to anything . If not then most likely you will not get any . if you hold it for long time to your own wallet then its still possible to claim yours just mention here what wallet did you use that time so we can share the right guide for you to claim your fork.
If only you had read the OP's post more carefully. He said he transfered bitcoin to the exchange in 2020, so there is no need to contact support because the coins were not on the exchange at the time of the forks.