A: I live in Miyazaki where the Miyazaki prefectural offices are located.

It takes about 20 minutes by bus from here. at

Join this sentence with the next.

It's not so far from my workplacemy workplace, it's not so far.

There are two reasons why I choose this area for my residence are two.

There are so many shops nearby such as a grocery store, convenience store and pharmacy.

When you start the list with an 'a' like this, the 'a' carries to the other items in the list.

This:
a grocery store, convenience store and pharmacy.

Is the same as this:
a grocery store, a convenience store and a pharmacy.

If I have muchd more money, I would move to a more quiet emnvironment.

Q: Where do you live ?

A: I live in Miyazaki where the Miyazaki prefectural office areis located.

It takes about 20 minutes by bus from here.

or

It takes about 20mins by bus from here.

There are two reasons why I choose this area for my residence are two.

In the US, this is more natural:

There are two reasons why I chose to live here.

There are so many shops nearby such as a grocery store, a convenience store and a pharmacy.

If I have muchd more money, I would move to morea quiet emvironmenter place.

We use subjunctive case for things we wish or situations which could be.

A: I live in Miyazaki where the Miyazaki prefecturale office are located.

It takes about 20 minutes by bus from here.

There are 2 reasons why I choose this area for my residence are twoo live here.

this sounds more natural but you could have "There are 2 reasons why I chose this area for my residence"

There are so many shops nearby such as a grocery store, a convenience store and a pharmacy.

If there is more than one it would be "such as grocery stores, convenience stores and pharmacies"

It faces the street and it is noisy.

or "It faces the noisy street"

If I have muchd more money, I would move to more quieter emvironment.

more quiet -> quieter