Yes, saying "will do" in an email is perfectly acceptable and commonly used in informal or professional contexts. It's a concise and friendly way to acknowledge a request or task and indicate that you will take care of it. For example:
Subject: Meeting Agenda
Hi [Name],
Could you please prepare the agenda for the upcoming team meeting?
Thanks! [Your Name]
Reply:
Hi [Your Name],
Sure, will do! I'll have the agenda ready by tomorrow morning.
Best regards, [Name]
In this context, "will do" shows a positive response, indicating that the person will fulfill the request. However, if the email is more formal or if you want to be more explicit, you can use alternative phrases like "certainly," "of course," "no problem," or "I'll be happy to." The choice of language depends on the level of formality you wish to maintain in the email communication.