Hello.You can create a members' area and define access to it https://guide.websitex5.com/en/support/solutions/folders/44000373872

Hello Marvin

Be aware that using protected pages where people can download from, will surely protect the download button to be seen by other people than the ones that has a password to the page - 

BUT -

It will not protect the file from downloading. If a user "finds" the files or know the filenames, they can be downloaded.

A way could be to make a special folder and protect this folder with password protection in a .htaccess file in the folder.

Another way could be to zip the files and specify a code for the zipping.

The methods can be combined. If you has PHP experience, you could use protected pages and also have a protection via  .htaccess for certain file-types and a script that uses the credentials from the protected-page credential to make a check for the folder credentials.

If not the file has very confidential information, then the protected page solution could be enough. If a file has confidential information, then the file could be zipped.