It is possible to edit multiple notes and chords simultaneously by selecting them with the marquee selector. In order to activate the marquee selector, click/tap and hold anywhere on or around the tab staff, and pull in the direction you would like to select the notes. When you release the marquee selector, the selected notes will become blue.
Now you can copy, move, or delete the selected notes and chords. In order to copy then, click/tap on one of the selected notes and the "copy" button will appear. Clicking that will copy the notes to the memory.
To paste the copied notes, scroll to the position you would like to put them and tap (and hold) on the beat you would like to paste. A paste button will appear, previewing the location of the notes if you choose to paste. Click/tap "paste" to place the notes.
You can also click/tap and hold the selected notes, and drag them around to move them to a different location.
And to delete the selected notes, simply drag them outside of the tap staff.