The next is one of many varieties of crosses with triple bars, where a common interpretation for each bar is Faith, Hope and Charity. These crosses are also used to show high status of office, favoured by the pope and used in Freemasonry. (See Triple Bar Cross)
Three X's at the bottom of a letter or email mean three kisses. XXX is an abbreviation for "extra", as in extra-large clothing, extra-strong alcohol, and so on. It is also an abbreviation of Amsterdam, which has three St. Andrew's crosses in its flag and coat of arms. 'Triple-x' is a chromosomal abnormality, where a girl has a bit more female in each cell. And for conspiracy theorists, XXX is the number 666 in Kabbalistic gematria.
But none of the three X's in the above paragraph have much connection with the Christian cross. Kisses are very nice; extra-large clothing is essential for extra-large people; extra strong-alcohol is extra-bad for you; Amsterdam is the capital of Netherlands; chromosomes are little rods of nucleic acids that don't even look like X's; and the numerology connection is with the letter "X", not a cross.
This style of Anchor Cross is another example.