Yes, you can use the same code on all subdomains of a verified website.
The ad tag of a zone is not tied to a specific hostname, so the same code works on blog.example.com, news.example.com, and so on, as long as example.com is verified in your Monetag account.
Please note:
Push Notifications and MultiTag on HTTPS sites use the sw.js file. Place it in the root folder of every subdomain where the tag is installed, since browsers treat each subdomain as a separate origin.
Statistics for all subdomains appear under the zone and the site it was created for. If you want to track a subdomain separately, add it as a separate site in the Sites section and create its own ad zones.
If you have any questions, you may contact our Support team via the email address support@monetag.com.