I had awent on vacation in the last year.

My company has about 30 staffs.

"staff" is uncountable (unless you mean a big stick a wizard or warrior might use).

We went to visited a beach city ofin Viet Nnam.

The name's of the beach city is Phu Quoc.

or "the beach city's name" name is "owned" by beach city.

Where We stayed isn a hotel near the beach.

We stayed there for 3 days and 2 nights.

you do something "for" a time period

We had a great time there.

The air is clean there,. I like it.

Two sentences needs . between

In the evening, Wwe had sea food for dinner at the night market.

lower case "w" as not a new sentence.

I drioved a round city by motorbike. and

drive is a strong verb and the past tense is therefore irregular

I bought some things there.

join these two sentences together.

I hadtook a vacation in the last year.

My company has about 30 staffemployees.

We went to visit a beach city ofin Viet Nam.

The name's of the beach city is Phu Quoc.

Where Wwe stayed i, there was a hotel near the beach.

I'm not sure what you're trying to say here.

We stayed there for 3 days and 2 nights.

We had great time there.

The air is clean there, I like it.

In the evening, Wwe had sea food for dinner at a night market.

I drioved around the city by motorbike.

I bought some things there.

This is correct, but it would be more natural to say "I bought a few souvenirs" or something like that.

My company has about 30 staffs.

Staff should not be plural

Where We stayed isn a hotel near the beach.

We had a great time there.

The air is clean there,; I like it.