The answer to all your questions is yes:

- you can store pdfs or other files either in Content Builder or in your sFTP
- you can use AMPscript to attach the files to your emails
- you can use AMPscript to dynamically match subscriber data with files and to create conditional statements
- you can match a file based on a filename, customer key, etc.

Some examples can be found in the ampscript.guide:
[https://ampscript.guide/attachfile/][1]


  [1]: https://ampscript.guide/attachfile/