Transcripts of a company's earnings calls are frequently made available on the investor relations page of the company's website (e.g. Snap Inc.)
Seeking Alpha has free transcripts available, however, you must setup a free account to view any transcript.
Factiva also provides quarterly earnings call transcripts. In the "Search Builder" type "transcripts" into the subject filter to limit your search results. Other methods include searching "Earnings Call Transcript".
On a Bloomberg terminal, on the single security main menu, type EVT then hit GO for a calendar of corporate events. Check for audio and/or transcripts of earnings calls in the results.
Additional resources for earnings (e.g. Earnings Report dates) include: TheStreet and Markets Insider.