When I send crypto from exchange to SafePal, it requests a Tag/Memo. What should I fill in?

Destination Tag or Memo is usually used by centralized exchanges to locate which wallet your funds belongs to, because centralized exchanges usually manage their funds in centralized custodial wallets. Since SafePal is a decentralized wallet, with you as the only one to manage all your funds, you don't need a Tag or Memo for any transaction. If you have to enter something into the space in order to send the funds, then please leave it blank or enter whatever you like. This won't impact the receiving of your funds.