Ok thank you all.
How can i prove that i bought coins before a specific date?
you can try to get it through the transaction history. I guess when you are opening the main tab and it will be available below the trading box. I guess there are some tabs and one of these tabs were the transaction history. You can try to check it dude. You can also go to your spot order tab maybe if there's
Every exchange allows the users to download their trading history data in the pdf or other format so user can use this for tax accounting or any other purposes.