Are you using a GPS unit to collect the new vertices or are you manually wanting to move them in ArcPad? Assuming you are using a GPS unit, then do the following:
In the drawing tools menu click the dropdown below the select button and click select & vertex editing. Then click the feature you would like to select and then click and hold on the screen until a new dialog box appears and select move to GPS and it will be moved to your current GPS location. Then click ok to accept the changes.
I hope this helps.