Indeed. So how do you access the files? Through some kind of code editor / ftp program? If you can view the files on the server through one of those, usually the .htaccess file will show up (if there is one). (Mind you, if you are doing this, then presumably you have server log in details, in which case you could use these to log in to the server, if you knew where the site was hosted, which should have a control panel of some kind. I find that's more reliable that editing online files through a desktop code editor.)
I would say just upload a fresh .htaccess file, but the danger is that it could overwrite an important one that's already there, so probably safer not to do that. The original developer might have had a reason to use a .htaccess file.
When I log into a site's control panel, I normally have to tick a box to "show hidden files" to view the .htaccess file.