I have set up a custom Password Reset policy in Azure AD B2C that allows the user to change their password while displaying custom branding elements depending on specific scenarios. This policy contains a step where the user verifies their Email Address by entering a verification code that is sent to their inbox.
From this post in the Microsoft Azure Feedback Forums: fully-customizable-verification-emails
It seems it is not possible to fully customise verification emails.
However, is it possible to perform some basic customisation of the verification e-mail within a custom policy? (text sent in the "From" and "Title" sections of the email and modifications to the text sent in the body).