This step refers to Microsoft Exchange deployments only.
Configure a Microsoft 365 Exchange Online Service Account
Note that the switch to Exchange Web Services (EWS) simplifies the Exchange Integration configuration by eliminating the need to use a service account.
How to Configure Microsoft Exchange Online Email Import Using EWS
Configure a Microsoft Exchange Server 2007, 2010, 2013, and Newer Email Service Account
How to Create an Email Service Account for Microsoft Exchange Server 2007, 2010, 2013, 2016, and 2019