from where I can get asus zenfone
The best option is to buy it from shop. You can also stole it, but didn't recommend that, because it's not right.
Ebay is a pretty good place for new and used phones from all around the world, if it is available in your country, then buying it directly from Asus or an approved retailer is obviously a better choice
In India, you can buy ASUS Smartphones from Flipkart.com.
Also, few models will be available offline and on ASUS Website - These are limited options.
It's easy man, just go to any samsung store and ask for the new galaxy s22 series. Thanks.