Shwmae! Sut dych chi? Sometimes the pronoun is run dy...di, eich...chi, ei...hi, fy...i and sometimes it's not - you'll hear both spoken.
In general terms:
eich cath = more formal
eich cath chi = pretty neutral
cath chi = more informal
"She sees you"
Mae hi'n eich gweld = more formal
Mae hi'n eich gweld chi = pretty neutral
Mae hi'n gweld chi = more informal