Why some headers appears with ###?

I don’t know why some headers appears between ## like in the image I uploaded
Thanks for the help!

it means that there is no translation available for that string in the language you are using.

Thanks for your reply (I’m learning how to use OJS)
And how I can translate it or help to do it?

There is a translation plugin available: GitHub - pkp/translator: PKP Translator plugin for OMP 1.1.1+ and OJS 3.0+

Detailed information about making translations is available here: https://pkp.sfu.ca/wiki/index.php?title=Translating_OxS