hello sir , how can i enable ecg app in other country ?

ECG must be government approved in country where Apple Watch was purchased, And in the country where the Apple Watch is used. Both must be true.

Apple Watch ECG countries

https://www.apple.com/watchos/feature-availability/#branded-ecg

You cannot unless they meet the following conditions;

For the ECG app to work on your watch the ECG app has to be approved by;

1. the government of the country in which the watch was bought and

2.the government of the country in which you reside.