Hello [Candidate Name],
Thanks for taking the time to speak on [date]. Based on our initial phone call, I found you very articulate and motivated, which is a great start. We'd love to put a face to the name and learn more about you.
After consulting with my boss/the team, we would like to invite you to our location at [address] for an on-site interview. You would be asked to sit down with me and expand on our phone conversation. I'll explain more about the position and what would be asked of you in this role if you're hired. Then, if there's time, we can take a quick tour of the location and you will possibly meet your prospective department head. The whole meeting should take no more than an hour.
If you're still interested in the position, please reply with your availability for the next 10 days and we'll get back to you as soon as possible. Thanks again and we look forward to meeting you in person!
[Hiring Manager Name]