Login Page Instructions
The instructions that appear on the Moodle login page are stored in the Moodle configuration property
auth_instructions. You can edit them from:
In the database, look for
auth_instructions in the
mdl_config table and change the value (which can be HTML):
select * from mdl_config where name = 'auth_instructions'
You may need to purge your Moodle cache to see changes.