You can find various PDF versions of Shri Gopal Sahastranaam online. Here are a few sources:
Shri Gopalo Mahipalah Sarvavedanga-paragah (The protector of cows, the king of the earth, well-versed in all Vedas).
Your authentic PDF should contain a verse like this early on: "Sri Gopala-sahasra-namam brahma uvacha: Sringa-vamsa-dharam krishnam, chandra-bhanum namamyaham..."
The full Śrī Gopāla Sahasranāma is found in:
If anyone has a clear, complete, and correctly chanted version (with or without commentary), please share. A version with dyana , nyasa , and phala shruti would be ideal.
Devotees and scriptures suggest several benefits of chanting these thousand names:
Klim Devah Kamadevah Kamabija-shiromanih (The Lord who is the god of love, the crest-jewel of the seed of desire).