Although all are free to receive in either one kind or both, it is worth recording that the church teaches that communion has a fuller form as a sign when received in both kinds.
The exact quite if the church is :
“Holy Communion has a fuller form as a sign when it takes place under both kinds. For in this form the sign of the Eucharistic banquet is more clearly evident and clearer expression is given to the divine will by which the new and eternal Covenant is ratified in the Blood of the Lord, as also the connection between the Eucharistic banquet and the eschatological banquet in the Kingdom of the Father.” GIRM 281
"The faithful who participate in the rite or are present at it, are made aware by the most suitable means possible of the Catholic teaching on the form of Holy Communion as laid down by the Ecumenical Council of Trent. Above all, they should instruct the Christian faithful that the Catholic faith teaches that Christ, whole and entire, and the true Sacrament, is received even under only one species, and hence that as regards the resulting fruits, those who receive under only one species are not deprived of any grace that is necessary for salvation.
Furthermore, they should teach that the Church, in her administration of the Sacraments, has the power to lay down or alter whatever provisions, apart from the substance of the Sacraments, that she judges to be more readily conducive to reverence for the Sacraments and the good of the recipients, in view of changing conditions, times, and places" (no. 282).
It is not at all clear to me what “fuller form as a sign” means, even considering the following sentence carefully. And then it almost seems to contradict itself in the following paragraph.
Not a high point in clear teaching by the church, IMO.