A thank-you note or telephone call after the visit is also considered polite and is an appropriate way to express your appreciation for the invitation.

拜访后的一封感谢信或一个电话也被视作一种礼貌，是一种表达你对收到邀请的感谢的适当方式。

youdao

Be prompt and well prepared for your follow up call or meeting and take the time to write them a thank you note.

你要尽量迅速行动，并且为后续的电话和会面做好充分的准备，还要抽时间给他们写一封感谢信。

youdao

After an interview, send a thank-you note (via E-mail or regular mail) to show your gratitude to the interviewer for taking the time to meet with you.

面试过后，发一封感谢信(通过电子邮件或是信件)来表达你对面试官花时间见你的感谢之情。

youdao

Either way, you send a thank you note and check your inbox compulsively for a week, waiting not-so-patiently for some sort of response.

FORBES: What to Do When You Don't Hear Back After a Job Interview

On a personal note, I want to thank you for the courtesy reflected in our prior discussions and also your letter.

FORBES: Magazine Article