I work as a police officer in Japan.

I’m a central government police officer from the National Police Agency.

That’s because I shouldneed to study practical and hands-on police works.

More natural to talk about "need" than "should" in this kind of situation.

Theseis works are is exhausting me.

I work as a police officer in Japan.,

This sentence and the next are better as one

I’m a central government police officer from the National Police Agency.

Now, I work at a police station in aAdatchi-kKu, Tokyo.,

Names of specific places should start with a capital letter
I believe the correct spelling is "Adachi," not "Adati"
This sentence and the next are better as one

That’s because I should study practical and hands-on police works.

Theseis works are is exhausting me.

I work as a police officer in Japan.

But, I’m not an ordinary police officer.

I’m a central government police officer from the National Police Agency.

Now, I work at a police station in aAdati-kKu, Tokyo.

That’s because I should study practical and hands-on police works.

Theseis works are exhaustings me.

I work as a police officer in Japan, but I'm not an ordinary police officer.

But I’m not an ordinary police officer.

These could be combined into one sentence to sound more natural and have better flow.

I’m a central government police officer from the National Police Agency.

Now, I work at a police station in adati-ku, Tokyo.

That’sI work there because I shouldneed to study practical and hands-on police works.

These works are is exhausting me.

I work as a police officer in Japan.

I’m a central government police officer from the National Police Agency.

Now, I work at the police station in adati-ku, Tokyo.

That’s because I shouldhave to study practical and hands-on police works.

Do you mean something like "field duty" by hands-on police work?

These works are exhausting me.

The job is killing me!/ These practices are exhausting...