Do I need to add any number before sending a text message from Taiwan Province Province to the mainland?

It's a good deal for you to use "Taiwan Province short message card"! The short message card of Taiwan Province Branch is specially used to send short messages from mainland China to Taiwan Province Province (it can also be sent to mainland China and international countries), because China Telecom/China Unicom's mobile phone needs 1 yuan/piece to send short messages to Taiwan Province Province, and it needs to start with 00886 when sending, and it only needs 0.38 yuan/piece at most when using the short message card of Taiwan Province Branch, and there is no need to add 00886 before entering the other party's number. It's on Taobao, and it's on the pat. You can find "Purchasing SMS Card" or "Taiwan Province SMS" or directly find "Taiwan Province Bank SMS Card yunlovejun".