
Multiple e-mail address entry was possible with SharePoint 2013 (comma-separated) and SharePoint 2010 (semi-colon separated). Unfortunately, with Microsoft 365 SharePoint you can only enter one account when using the e-mail address option. I would recommend creating/using a distribution list that you would populate with the users required to receive the access requests and this is the account that you would enter in that e-mail address field.
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