There are the following two expressions in Japanese.
Actually, the usage of this is ambiguous even for Japanese people, but there is a clear difference between the two.
"時" represents a clear time
"時" is used to represent a clear time.
Sentences that are expressed using "時".
・ Customers must disinfect when they come here.
・ When I come here, I usually order beer
When talking about clearly separated times, use the kanji "時".
"とき" represents an assumption (case classification).
・ Let's talk when Mr. A comes here.
In the sentence, two patterns are assumed, one is "come" and the other is "not come". It is used to mean when ⇨ when. Therefore, "when you come" can be rephrased as when you come.
This article is not well understood by Japanese people. It was the proper use of "time" and "time". When writing a sentence, if you can write it carefully so as not to be confused, there is no doubt that it will be noticed by others.