I(I am) studying aquaculture of inland region.

If you use I and an "ing" verb, you need the "am" in between.

Since this is a title, you can omit the "I am" entirely, but you couldn't in a random sentence. If you do omit the "I am", then you would put a capital S on studying.

I am studying aquaculture of (an inland region / inland regions) for my job.

If you're studying one inland region, you should say "an inland region".

If you're studying more than one inland region, then "inland regions" is better.

SinceIn august of 2023, iI found this company in Tokyo.

"found" is a single event, so "In" is better than "since"

My job is support foring developing countryies and our objectives are to achievement of Sustainable Development Goals No,.14" Life below water" and No,. 2 "Zero Hunger".

Abbreviations like "No." use a full stop, not a comma.

Pay attention to plural vs singular.

But, Mmy background was as a physical education teacher in elementary and junior high school.

Therefore, iI am studying now about aquaculture in japan and fishier ringtand fishing in Japan now.

I'm guessing "fishier ring" was supposed to be fishing.

Country names are capitalised in English.

In the future, iI'll work in (another country / other countries) as a development consultant for my company.

Again, the difference between singular and plural is important. If you have one other country in mind "another country" is better, if you're going to be going into multiple countries, then "other countries" is better.

Today is rainy, but tomorrow is a holiday.

I want to sleep in my betd for a lot ofng time.

And moreOn top of that, I'll go to Nagano in Aichi prefecture for my job about, ato attendo a other country people in the training program of aquaculturen inland region aquaculture for one month.

"inland region aquaculture" is used instead of "aquaculture inland region" as "aquaculture" is the noun here and inland region is being used to specify which type of aquaculture you're studying.

Not fully sure what "atendo a other country people" should have been.

"about" is not something that is usually followed by a pause in English.

I am studying aquaculture ofin inland region.

I studying aquaculture ofin inland region foras my job.

Since aAugust of 2023, iI found this company in Tokyo.

Months and "I" are always capitalized.

My job is to support for developing country and our objectives are to achievement of the Sustainable Development Goals No,. 14 "Life below water" and No,. 2 "Zero Hunger".

I am not sure whether you wrote "No. 14" instead of "No. 1"

But, Mmy background was that I was a physical education teacher in elementary and junior high school.

Therefore, iI am studying (right) now about aquaculture in japan and fishier ringties in Japan.

Countries are always capitalized.

In the future, iI'll work in another country as a development consultant for my company.

Today is rainy, but tomorrow is a holiday.

I want to sleep in my betd for a lot ofng time.

And moreMoreover, I'll go to Nagano in Aichi prefecture for my job about, atendo and meet people from other country peopleies in the training program of the aquaculture inland region for one/ a month.