"Word_Press" appears in website URL

I have taken over administration of my church WordPress website. Previously the URL was https://www.tbc.org.au. But now it has become https://www.tbc.org.au/Word_Press/. I don’t know how this happened.

I want to get rid of the Word_Press. I have gone to Permalink Settings, and all the Common Settings there include Word_Press. I don’t know what else to do.

I should mention that the site no longer displays on mobile devices, and I presume this is the reason.

I’d be very grateful for guidance on what I should do. Thank you.