The internship offer letter should include the start and end dates of the internship, as well as the number of working hours per week. Sample internship offer letter template.Take this easy-to-use template and draft a simple offer letter to send out to them. Dear (student's name): I am pleased to confirm your acceptance of an internship as (Title) in the (Department Name) with (Organization Name). These basic sample offer letters consist of "core" data that should be included in an offer letter.