AnOne aspect of Japanese culture that sometimes surprises foreigners is the use of personal seals, called “HANKO（ハンコ）”.

Optional

It’s a small cylinder made of wood, stone, or plastic that is engraved with one’s own surname on one side of the edgside.

“Of the edge” confused me a little. Edge, when referring to 3D shapes like a cylinder, refers more so to the lines that connect the faces/sides.
The “one” to “the” change is optional, I just preferred how “the” sounds since “one” felt slightly repetitive.

There are many types of INKAN（印鑑） and the Japanese people usually have several INKAN.

“The” is unnecessary since you have said “people” after Japanese.
It would be better to say “The Japanese usually…” or “Japanese people usually…”

Another type of INKAN for daily use, called MITOMEIN（認印）, which doesn’t need to be registered, also plays anis important role when we open bank accounts or rent apartments.

Changing it to “is important…” is optional - just another more concise way of saying the same thing.
I don’t think “also” is entirely necessary here, as it implies that you are adding onto something that you’ve already said about the topic (the topic in this case is mitomein) or that it shares the following quality with the previous topic (jituinn). What I mean is that it could imply that you’ve already commented on mitomein, or that mitomein shares the quality of being important in opening bank accounts and renting apartments with jituinn.

Other than that, occasions to use it is becoming fewer and fewerthem/inkan are becoming less frequent.

Is —> are (occasions is plural, regardless of whether you replace it with them/inkan or not)
“Them” is an optional edit - my thought process was multiple types of inkann = them
“Fewer and fewer” is optional, I just changed it because it isn’t something I usually hear.

Before, we needed it even when receiving any goods delivered by Ccourier.

While many people usually order their original INKAN at a special shop, we can buy it even at a 100-yen shop, where ready-made INKAN for the most popular family names sell at the price of 100 yen.

An aspect of Japanese culture that sometimes surprises foreigners is the use of personal seals, called “HANKO"hanko"（ハンコ）”).

It’s a small cylinder made of wood, stone, or plastic that is engraved with one’s own surname on one side of the edge.

There are many types of INKAN（印鑑） and theseals, or "inkan" (印鑑), and Japanese people usually have several INKANof them.

The most important one is called JITUINN"jituinn"（実印）), which is required to bfor more official affairs, like registereding at the local government office.

It’s necessary when wefor buying houses or cars.

Another type of INKAN for daily use, called MITOMEINinkan we use in our daily lives is called "mitomein"（認印）), which doesn’t need to be registered, also but still plays an important role for when we open bank accounts or rent apartments.

Other than that, occasions to use it is becoming fewer and fewerit is becoming more and more seldom to use them.

Before, we even needed it even wheupon receiving any goods delivered by Ccourier.

While many people usually order their original INKAN atinkan from a special shop, we can buy it eveneven buy one at a 100-yen shop, whereich sells ready-made INKANinkan for the most popularcommon family names sell at the price offor 100 yen.

Therefore, it would be possible to get INKANready-made inkan of other people’s names and use them in place of others.

But it’s totally the cascompletely true.

An aspect of Japanese culture that sometimes surprises foreigners is the use of personal seals, called “HANKO（ハンコ）”.

I would probably write "hanko" in lowercase.

It’s a small cylinder made of wood, stone, or plastic that is engraved with one’s own surname on one side of the edge(or last name, or family name) on one end.

There are many types of INKAN（印鑑） and the Japanese people usually have several INKAN.

I'm not really clear what an inkan is here because you switched from hanko to inkan without introducing what an inkan is.

Another type of INKAN for daily use, is called MITOMEIN（認印）, which). Though it doesn’t need to be registered, alsoit plays an important role when we open bank accounts or rent apartments.

Other than that, occasions to use it isa hanko are becoming fewer and fewer.

Before, we needed it even when receiving any goods delivered by Ccourier.