I did this on my first kite and board and it did not really help when selling the kite.
I am currently trying to get my hands on sail tape (any idea where to find that kind of stuff in Melbourne?) and then write my name & number on the tape.

Use a Sharpie pen. You can clean it off with metho or eucalyptus.

Write your name and number on the board on the bottom of the board next to each of the fins. It wears off if you write it on the fins.

Most kites have a manufacturer's label with patent and made in stuff on it. There is room to write your details on their. The label is non porous so it is easy enough to clean it off. Cabrinha have an owners label for you to write stuff on.

If you want your details so you can identify stolen kites then open the leading edge zip and write your name and number inside as well.

Thanks Guys.....

paint marker - looks like a texta. more durable but comes off with turps. newsagents sell them
good tip puppet about id under the pads

Do what I did with my surfboards, resin your license no in. It's somewhat permanent but can be sanded back and removed back to original resin. You need a surfboard repair kit. Simply put your details / business card on the board, next to the fins or pads and glass over with a clean piece of fibreglass cloth. Resin over, sand back lightly and presto!

Hi Guys,

Please DO NOT use Acetone on your board!!!!

Use hair spray as the texta is cellulose based and will come off easier and cleaner without messing up your board.

Acetone is an extremely harsh solvent and will melt the epoxy.

DM