It is recommended to send a thank-you note following a job interview, and sending it via email is appropriate. It can get to the interviewer quickly and can reiterate the level of interest in the job.
When writing a thank-you note following a job interview, it is important to thank the interviewer for taking their time to meet the candidate. The letter can also be used as a follow-up to further explain the skills of the candidate and to address any concerns the candidate may have. This type of note should be brief and to the point as much as possible.