Unicode error warning red message

To fix this, we need to alter the database using this command

ALTER DATABASE `dbname_moodle` DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;

How to add a regular user to become Site Administrator in moodle from backend

Go to mysql and select the right database.
Then select the userid that your username is using in mdl_user
Then update mdl_role_assignments set roleid and contextid = 1 where your userid = thenumber above