The exercise of updating the password hash that you reference is only necessary if you have users that only have a 10G password hash. If they also have 11G or 12C (or whatever is the minimum level you desire them to have) then there is no need to change or update individual users - just skip to setting the sqlnet.ora parameters described below to enforce the minimum authentication protocol usage you desire.
Check your password hash versions for each user with this query:
select username, password_versions from dba_users order by 2;
If there are in fact users with only a 10G hash as shown above, then they must reset their password to have Oracle create valid hashes for 11G or 12C authentication protocols. You cannot do it for them without knowing what the actual password was (knowing the 10G hash will not help). Assuming that they have clients like sqlplus that support handling expired passwords, you can force users to do it themselves by expiring their accounts with
ALTER USER username PASSWORD EXPIRE;
As @EdStevens warned however, not all client applications can handle this and may just prevent the user from logging in entirely. You will have to use your best judgement on how to force each user to change their password.
Once all of your users have the minimum level of hash that you require, set the
sqlnet.allowed_logon_version_server parameter on your server as described here (https://docs.oracle.com/en/database/oracle/oracle-database/19/netrf/parameters-for-the-sqlnet.ora.html#GUID-B2908ADF-0973-44A9-9B34-587A3D605BED) to enforce that minimum level of authentication protocol usage going forward.
When the final minimum values for the sqlnet.ora parameters are set, obsolete hash values will be deleted automatically whenever a user changes their password. There will be users that still show "10G" or other obsolete password versions for some amount of time after you set the sqlnet.ora parameters. This is ok, as the sqlnet.ora settings will not allow those less secure hash values to be used for authentication.