In order for you and the users in your account to find files more easily, it is possible to create and use custom filters and tags that can be applied to different files to better categorize them.
To set up the custom filters, click on your initials on the top-right corner and select Settings. Then from the left menu choose Library settings. In the new page, you will be able to create new custom filters and assign them a name.
Once the custom filters are defined, you will be able to assign specific filter values to each file by clicking on the file and adding a filter value in the dedicated field in the Metadata section on the right.
Now all the files tagged with a custom value are searchable from the main library using the dedicated filter.
The same way you can create custom filters, it is also possible to create custom tags. Once you create/add the tags, you can use the Tag filter in the Library to help you narrow down your file search.