The epiclesis is a part of Eastern anaphoras where the Holy Spirit is invoked upon the gifts that it might transform them. As an example Here is the epiclesis from the Divine Liturgy of St. John Chrysostom (I’m going to put all of these prayers in red just to make this post a bit easier to parse out):
Priest: Again we offer to Thee this noetic and unbloody sacrifice; and we beg Thee, we ask Thee, we pray Thee: Send down Thy Holy Spirit upon us and upon these Gifts set forth.
Deacon pointing with his orarion to the diskos: Bless, Master, the Holy Bread.
Priest: Make this bread the Precious Body of Thy Christ,
Deacon pointing to the chalice: Amen. Bless, Master, the Holy Cup.
Priest: And that which is in this Cup, the Precious Blood of Thy Christ,
Deacon pointing to both: Amen. Bless them both, Master.
Priest: Changing by Thy Holy Spirit.
Deacon: Amen, Amen, Amen.
This sort of invocation of the Holy Spirit is what is known as an explicit epiclesis (because there is an explicit mention of the Holy Spirit).
The Roman Canon, which is exclusively used in the EF of the mass, and is also used as Eucharistic Prayer I of the OF of the Mass contains no explicit epiclesis. Instead, one of the prayers is seen to be an implicit epiclesis. This prayer would be the ‘Quam oblationem.’
Quam oblationem tu, Deus, in omnibus, quaesumus, benedictam, adscriptam, ratam, rationabilem, acceptabilemque facere digneris: ut nobis Corpus et Sanguis fiat dilectissimi Filii tui, Domini nostri Iesu Christi.
Bless and approve our offering; make it acceptable to you, an offering in spirit and in truth. Let it become for us the body and blood of Jesus Christ, your only Son, our Lord.
(A more literal translation from the Latin reads: Which offering do thou, O God, vouchsafe in all things. To bless, consecrate, approve, make reasonable and acceptable: that it may become for us the Body and Blood of thy most beloved Son our Lord Jesus Christ.)
Notice that it does not make mention of the Holy Spirit. The prayer then, is said to implicitly invoke the Holy Spirit to consecrate the gifts (“Bless and approve our offering”), even if it makes no specific mention of the Holy Spirit. Eucharistic Prayers II, III, and IV from the OF of the mass, however, have prayers which seem to be more closely modeled after the explicit style of epiclesis used in Eastern liturgies:
Epiclesis from Eucharistic Prayer II:
Haec ergo dona, quaesumus, Spiritus tui rore sanctifica, ut nobis Corpus et Sanguis fiant Domini nostri Iesu Christi.
Let your Spirit come upon these gifts to make them holy, so that they may become for us the body and blood of our Lord, Jesus Christ.
Epiclesis from Eucharistic Prayer III:
Supplices ergo te, Domine, deprecamur, ut haec munera, quae tibi sacranda detulimus, eodem Spiritu sanctificare digneris, ut Corpus et Sanguis fiant Filii tui Domini nostri Iesu Christi, cuius mandato haec mysteria celebramus.
And so, Father, we bring you these gifts. We ask you to make them holy by the power of your Spirit, that they may become the body and blood of your Son, our Lord Jesus Christ, at whose command we celebrate this Eucharist.
Epiclesis from Eucharistic Prayer IV:
Quaesumus igitur, Domine, ut idem Spiritus Sanctus haec munera sanctificare dignetur, ut Corpus et Sanguis fiant Domini nostri Iesu Christi
Father, may this Holy Spirit sanctify these offerings. Let them become for us the body and blood of Jesus Christ our Lord
Notice how all of these prayers explicitly mention the Holy Spirit. From the Eastern perspective at least, the presence of an explicit epiclesis in Eucharistic Prayers II, III, and IV from the OF of the mass is an improvement over the old Roman Canon/Eucharistic Prayer I. I’m personally not too sure if I buy the idea that the Roman Canon is somehow deficient because of its lack of an explicit epiclesis (it was fine before the schism, after all), but I do know many Orthodox Christians who do.
You certainly might have seen an EF of the Mass on EWTN but if so that was very unusual.