1, mobile phone access settings-fingerprint, face and password/fingerprint and password-unlock screen password-enter password twice;
2. In the password setting interface, click "Other password types/password options" and you can choose to set mode password, 4-digit password, 4- 16-digit password and mixed password.
If you still have more doubts, you can enter vivo official website-My-Online Customer Service-Enter labor and consult online customer service feedback.