How does Xiaomi mobile phone set different contacts for different SMS ringtones?

Mobile phones are basically only equipped with ringtones, not SMS ringtones. You may have to rely on third-party background plug-ins, but the vendors with this function in the operating system seem to be not active. The previous answer doesn't matter-it's so simple to add or distribute ringtones, which idiot still uses Baidu to ask? Self-righteous attitude, so the title is not clear, people obviously ask about the distribution of SMS ringtones among different contacts, not SMS! foolish