en_tn/act/19/21.md

Paul completed his ministry

Paul completed the work that God had for him to do in Ephesus.

Macedonia and Achaia

These provinces are modern day Greece.

he decided in the Spirit

Possible meanings are 1) Paul decided with the help of the (Holy) Spirit" or 2) the Spirit led Paul to decide.

I must also see Rome

"I must also travel to Rome"

But he himself stayed in Asia for a while.

It is made explicit in the next few verses that Paul was staying in Ephesus.