Indeed, e-mails have been sent with a request to enter your personal e-mail address in SAP My Apps by the HR Helpdesk and the DICT Helpdesk.
The subject of this e-mail is "Registratie privé-e-mailadres in SAP MijnApps / Registration private e-mail address in SAP MijnApps".
These e-mails are not spam or phishing, they are legitimate and it is therefore really necessary that you enter your personal e-mail address in SAP My Apps as soon as possible, as described in the instructions of this e-mail. This address can then be used for things like resetting your password.
If you do not have a personal e-mail address yet, you can always create one via your e-mail provider, or at Google or Microsoft.
If you do not enter your personal e-mail address, you will continue to receive reminders in the future until you do.