If you are an employer and reviewed all resumes, finally you have to choose some specific people for interview. However, this process is not limited with decision because you need to write an email about interview invitation.
Firstly, you should point that you would like to interview with that person for the applied position at your company. Then, you can start the body and use a typical salutation such as hi or hello. You should thanks to applicant for applied your job opportunity. After this, you can explain why you decided to invite this applicant for interview. For instance, you can say that we are impressed by your CV and want to know more about you. You should indicate the type of interview such as via Skype or at office. Also, you can add any details about what are you requiring from applicant or what should he bring. In addition, you might specify the duration of interview.
In the last part you have to offer three different dates to applicant and ask to let you know about when he will be suitable. Also, you need to note that, if there is a problem with dates or any kind of things, he should contact with you any time. After all these information, you can conclude with typical words such as best regards. If you want to make a difference or you want to be warmer, you can use a sentence like look forward to meeting you. However, your way of using language depends on the type of job and company. If you have a more official company, you should be more professional and formal.