Hello @Arutprakasam ,
Thanks for reaching out.
You may accomplish this by creating 2 separate custom policies.
Example:
The first policy is "sign up without verification.xml", which is a sign-up policy that requests the consumer for their email address and phone number before creating a new user with these designated as unverified. This custom policy can be activated during the Account Creation process.
The second policy is "sign in with verification.xml", which is a verification policy that checks the unverified email address using the built-in email message, and then the unverified phone number using the built-in phone call or text message. This custom policy can be activated at the Application Complete phase.
You can find detailed custom policy samples from here which may useful. Additional, there is a feedback submission already to add "delayed verification" feature within built-in way of doing rather than using custom policy (like with a single checkbox to delay user verification) here is link for your reference so would request you to up-vote this feature request so our product team prioritize and may develop this feature accordingly.
Here are some similar threads for your reference. Hope this helpful.
https://learn.microsoft.com/en-us/answers/questions/135286/how-to-do-email-verification-out-of-azure-b2c-sign.html
https://github.com/chrispadgettlivecom/active-directory-b2c-custom-policy-samples
https://stackoverflow.com/a/54474425/15035732
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