Part of a moderation feature enablement request, one of my clients was very keen to have deletion option for Microsoft Teams channel owners. This is a fair request as some channels would require control on end-user actions, specially in EDU sector scenarios.
Even though this sounds like moderation feature, deletion of sent messages is a separate feature which is beyond the moderation options in Teams. If you are looking to enable moderation in Teams, have a quick look at my post here on how to that – Configuring Channel Moderation for Microsoft Teams
Enable the functionality (Globally enabled, No Team/channel level option unless you create a custom policy for group-wise rollout)
Login to your Office 365 tenant as an administrator and navigate to Teams Admin center
From Teams Admin center, navigate to Messaging Policies
Click on the default messaging policy (Global-wide). This change affects globally across the entire tenant. However, you can switch it OFF again whenever you think it is inappropriate.
And, simply switch ON the “Owners can delete sent messages” option there.
Owners should now be able to delete the sent messages by users which may be inappropriate as per organization/policy guidelines.