Number of payments with online purchase

I see this option when I'm making purchases online...
お支払い回数

How do multiple payments work?

Is it like a "subscription" in the sense that the websites holds my credit card information and each month charges me until my purchase is paid off?

Or do they make a hold on my account for the total of the purchase?

I want to make a large purchase (~120,000) and pay in three payments, but want to know if the total will be charged right when I check out or if there will be monthly payments.

https://www.sofmap.com/topics.aspx?id=guide&sid=401

Is your card one that was issued outside Japan? If so, there is a chance that only one-off payment is allowed.

This is installments, and whether this is allowed is up to what facility your card issuer provides you.
In Japan, some card issuers charge no interest for payment in 2 installments (instead of one-off), or in one deferred payment for the next bonus season.