I just subscribe theo Disney Plus membership for one year. I just subscribe to Disney Plus for one year.

You can also refer to Disney Plus as Disney+ Subscribe to ~~~

I just subscribed to the Disney Plus membership for one year. I just subscribed to the Disney Plus membership for one year.

I just subscribed to the Disney Plus membership for one year. I just subscribed to the Disney Plus membership for one year.

You want to use past tense here since you've just done this.

In Korea, it started to service sincepremiered yesterday, and many Koreans are subscribing. In Korea, it premiered yesterday, and many Koreans are subscribing.

Premiered - 초연 If you use many make sure what comes after it is plural

In Korea, it started tothe service sincetarted yesterday, and many Koreans are subscribing. In Korea, the service started yesterday, and many Koreans are subscribing.

In Korea, it started to service sincthe service became available yesterday, and many Koreans are subscribing. In Korea, the service became available yesterday, and many Koreans are subscribing.

It's more natural to say, "the service became available yesterday" or "it's been available since yesterday."

My children really like to see Disney and Pixar charactoers, that's why I subscribed to the service. My children really like to see Disney and Pixar characters, that's why I subscribed to the service.

My children really like to see Disney and Pixar charactoers, that's why I subscribed to the service. My children really like to see Disney and Pixar characters, that's why I subscribed to the service.

My children really like to see Disney and Pixar charactoers, that's why I subscribed to the service. My children really like to see Disney and Pixar characters, that's why I subscribed to the service.

In English, we say we "subscribe to" something.

On the serviceDisney+, I notice that Marvael and National Geographic contents are on there. On Disney+, I notice that Marvel and National Geographic contents are on there.

It would be better to use their branding instead of repeating service

On the service, I noticed that Marval and National Geographic contents are theravailable. On the service, I noticed that Marval and National Geographic contents are available.

On the service, I noticed that Marvael and National Geographic contents are there. On the service, I noticed that Marvel and National Geographic contents are there.

Again, you want to make sure to use past tense.

I think, my family will be falldrown in the ocean of the contents. I think, my family will be drown in the ocean of the contents.

I think, my family will be fall into the ocean of the contents. I think my family will fall into the ocean of the contents.

I think, my family will be falling into the ocean of the contents. I think, my family will be falling into the ocean of the contents.

Grammatically, it's natural to say "to be doing x." The past participle is important.