@Sakshi The token return by Custom policy in B2C by default includes acr claim containing policy name. If you want to remove this claim and use tfp claim instead, you need to set AuthenticationContextReferenceClaimPattern to None in JWTIssuer technical profile as highlighted below:
This will remove the acr claim from the token and to add tfp claim, add below claim id under claim schema in your TrustFrameworkBase.xml or TrustFrameworkExtensions.xml file.
Finally, add below output claim in your RP file (e.g., signup_signin.xml) :
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