Best practice for using PIN and PASSWORD using AD B2C

Hi I am working on AD B2C , where I am using Azure AD B2C for Authentication and Authorization.
I have created a custom policy to Register a user using phone number verification.
My Main concern is that ad b2c does not support PIN(Not Password)
How can I use pin and Password for Authentication .

I have used a custom attribute

<ClaimType Id="extension_UserPin">
                <DisplayName>User Pin</DisplayName>
                <DataType>string</DataType>
                <DefaultPartnerClaimTypes>
                    <Protocol Name="OAuth2" PartnerClaimType="extension_UserPin" />
                </DefaultPartnerClaimTypes>
                <UserHelpText>Enter your PIN</UserHelpText>
            </ClaimType>

Which looks not a good practice .
So can anyone expert tell me this how to do this Pin And Password