You can only delete your ShopeePay account by deleting your whole Shopee account. If you plan to do so, go to the Me tab > ⚙ > Request Account Deletion > OK.
⚠️Note
Account can only be deleted if you have withdrawn all funds.
You will need to contact Shopee Customer Service to withdraw any remaining funds in both your ShopeePay sub-wallets.
Alternatively, you can withdraw your funds via the ShopeePay page, before deleting your account.