I'm ttryin 2 find out if someone claimed my son on their taxes

You can't, at least not directly. If you believe that you are the person who should claim your son as a dependent on your taxes, then do so. If someone else has already filed and claimed your son, then you will find that you can not e-file, as the IRS computer will recognize the discrepancy and prevent you from filing. So file a paper return, claiming your son. The IRS will eventually follow up and resolve the issue.

hello im trying to find out if the father of my children claimed our children!?! how do i know so i know if i can!?!

Please do not double post questions. If you read post #2 you have your answer. Or read the response to the other thread you started, here:
https://www.askmehelpdesk.com/taxes/hello-name-sabrina-624852.html

Please ask a follow-up question if there is anything you don't understand in the responses.