ECDH uses elliptic curve math for key exchange.
ECDHE is the ephemeral version — generates new keys per session for Perfect Forward Secrecy.
TLS 1.3 exclusively uses ECDHE for key exchange. "E" in ECDHE = ephemeral = new key each session = forward secrecy. If you see "ephemeral" in a cipher suite, forward secrecy is provided.