If you are baptised and you usually receive Communion (the bread and wine) then you’re welcome to do so here. If you don’t usually receive Communion, or you have no idea what we’re talking about (!), then you can come forward with everyone else at this point in the service and receive a blessing. (The priest will say a very short prayer for you, resting his/her hand on your head.) If you hold your service sheet when you come up the priest will know that you don’t intend to receive Communion. Or, if you prefer, you can stay in your seat. If you’re unsure, just ask someone.