Replay to email received from the activity log in the classic UI by pressing replay all

HI,

I saw in instance (that I don't have access to) that there is an option to add to the activity log the ability to replay/replay all/forward  to an email that was received by pressing a button.

Can any one help me with this requirement?

I do know that the ability to replay to an email is in the workspace but my customer wants to work in the classic ui and he wants the ability to replay to an email from the activity log it self.

Hope I was clear.

Thanks to any one that answer,

Lior Grinberg