You cannot change your email address to login to PayPay for Developers.
If you would like to use a different e-mail address, please register a new e-mail address with that e-mail address.
If you are already a registered merchant that has access to the production environment, please the change the login address from the PayPay for Business account.
When changing the email address for the PayPay for Business account, the login address for the PayPay for Developers account linked also changes.
Please refer to the below on how to change email addresses in PayPay for Business
https://paypay.ne.jp/help-merchant/b0023/
Note: Information regarding specification changes are sent irregularly from PayPay for Developers. If you wish to change the address of the recipient please check here.
Note: If you wish to delete the mail address registered to PayPay for Developers please check here.