OJS create new journal_settings

Description of issue or problem I’m having:
I want to add doi information to journal_settings table, i can do this but i dont know how i can get this information from my bootstrap template; but i yes can get another information of the journal_settings table

Steps I took leading up to the issue:

What I tried to resolve the issue:
I user $journal-> getData(‘doi’)
$journal-> getLocalizedData(‘doi’)
$journal-> getSettings(‘doi’)
$journal-> getLocalizedSettings(‘doi’)
But nothing happends

Application Version - e.g., OJS 3.1.2:

Additional information, such as screenshots and error log messages if applicable:

really apreciate your help