Be careful, places like CoinBase are only giving a list of transactions.  That's not a Form 8949 acceptable attachment.  They need to sign up (and pay) for CoinTracker which give the proper documentation for the tax return. Other places like Robinhood Crypto do a very nice job. For your specific question, if the csv file can be formatted into Excel in the proper format of a Form 8949 Attachment then yes, you can attach a .pdf copy of that file, just not the.csv file.