Restrict Email Delete Access in Outlook Using Group Policy

Is there a way to restrict users from deleting email from Outlook using Group Policy or some other setup?

Or else is there any email client or provider having functionality such that admin can restrict users from deleting the emails?

If you use Exchange, you should read up on Messaging Records Management. Combine retention policies and litigation hold policies for the desired effect. This can also be done in O365. License requirements apply.

I want to confirm something listed below:

1. What is the version of your exchange server?
2. Which user does you want to restrict? Mailbox owner or mailbox delegate?

If you want to restrict mailbox owner from deleting items, you could refer to the blog to prevent users from permanently deleting email, here are some detailed step for your reference.

If you want to restrict mailbox delegate from deleting items, only assign mailbox folder permission to these delegates, running the following command to assign permssion:

Add-MailboxFolderPermission -Identity [email protected]:\inbox -User [email protected] -AccessRights Reviewer

Explanation on folder permission: https://docs.microsoft.com/en-us/powershell/module/exchange/add-mailboxfolderpermission?view=exchange-ps#parameters