Thanks for your answers. I'll buy a pencil, that would be the easiest way. I am coming from forscore, where I organize over 2500 chordsheets as pdfs, which are already on my iPad. But as Damir wrote, I'll switch to text-based chords, for my collection of backingtrack-songs, which I use with stage-tracks. So it is easier to transpose - without a pencil. A lot of my songs are german, it is not easy to find them correct in the web. There it would be easier/faster to use the existing pdfs.