Preencodable ID cards

An ID card structure comprising an envelope having front and back protective sheet components sandwiching a frame member having a well opening suitable to accommodate an information-bearing document therein, at least one of said front and back sheet components having a magnetic encoding capability provided by a layer of magnetic material in the form of a stripe extending over a predetermined area of the outermost surface of the sheet component, and including a removable interleaf member positioned within said well opening of the frame member, the dimensions of the interleaf member being substantially the same as the dimensions of the well opening so that when the interleaf is in position within the well opening of the frame and both front and back sheet components are superposed in sandwiching disposition thereto, substantially all portions of the magnetic stripe material are supported by a substantially flat surface provided by the frame and interleaf member, so that the magnetic stripe material may be encoded prior to insertion and sealing of an information-bearing document within the ID card structure.