How long does it takes for Domain Verification at step 2 to complete?

If you have bought a CDN plan from us and during the setup of the plugin at Step 2 after making the changes to your DNS, you'd get to see the below screen :

Now, the time required for the changes made to A/CNAME records to reflect global DNS servers depends upon the TTL(Time To Live, or TTL for short, is the sort of expiration date that is put on a DNS record. The TTL serves to tell the recursive server or local resolver how long it should keep said record in its cache. The longer the TTL, the longer the resolver holds that information in its cache. The shorter the TTL, the shorter amount of time the resolver holds that information in its cache.) value set.

That's the reason we recommend the users keep the TTL value greater than or equal to 300 or less than or equal to 600.

Note: Some hosting providers do not allow modifying the TTL values and keep it to the standard TTL value which is 3600 secs(1 hour).In such cases, you'd just need to update the A/CNAME records in your DNS and wait for the updated value to reflect the global DNS servers.

You can monitor the status here: https://dnschecker.org/