IF the preference share is irredeemable then it’s equity. If the preference shares are redeemable , then they are considered as debt and actually, the dividend paid is considered as finance cost and it’s included on the income statement.
Preference shares can be both equity and debt. If the shares are redeemable, then it is debt (something like a bond).If the shares are not redeemable, then the preference shares are part of the equity.