Can て be a particle?


Recently in Japan I saw the following sentence:

> お支払いは窓口にて、お願いします。

My husband explained that the emphasis was one could ONLY order at the window.

Being a native speaker, he is unable to really explain the grammar or how to
use this.




Particle used here is
[にて](https://en.wiktionary.org/wiki/%E3%81%AB%E3%81%A6)--a more formal version
of で.

The sentence is equal to the following except for being more official:

> お支払いは窓口で、お願いします。

The sign asks customers to pay at the window.

Similarly to で, [にて](https://kotobank.jp/word/%E3%81%AB%E3%81%A6-592418) is
used to indicate place of the action, time of the action, method, or reason.

