Apple 80-Column Text Card
The Apple 80-Column Text Card was an expansion card for the Apple IIe computer to give it the option of displaying 80 columns of text instead of the usual 40 columns.  Two models were available; the cheaper 80-column card had just enough extra RAM to double the video memory capacity, and the Extended 80-Column Text Card had an additional 64 kilobytes of RAM, bringing the computer's total RAM to 128kB.

VisiCalc and Disk II made the Apple II very popular in small businesses, which asked the company for 80-column support, but Apple delayed improving the Apple II because for three years it expected that the unsuccessful Apple III would be the company's business computer. The cards went in the IIe's "Auxiliary Slot", which existed in addition to the 7 standard Apple II peripheral slots present on all expandable Apple II series machines.  Although in a separate slot, the card was closely associated with slot #3 of the 7 standard slots, using some of the hardware and firmware functions that would have otherwise been allocated to slot 3, because third-party 80-column cards such as the Sup'R'Terminal had traditionally been placed in slot 3 on the earlier Apple II and Apple II Plus machines. Therefore the user could enter 80-column mode by issuing the command "PR#3" or "IN#3" in the BASIC prompt.

The "extended" version of the card features a jumper block (J1) that when installed enabled the double high-resolution capability. Since early "Revision A" Apple IIe motherboards were incapable of supporting the bank switching needed for the enhanced graphics mode, the block needed to be removed to disable the feature.

As with many Apple II products, third party cards were also produced that performed a similar function, and some types of 80-column cards were available for the older Apple II and Apple II Plus, which did not feature a dedicated slot for this card.  The Apple 80-Column Text Card was itself a clone of these earlier third party cards.

Soon after the release of the Apple IIe, 80-column text support became a basic requirement of many software packages.  Later, 128kB (and therefore the Extended card) became a minimum requirement for major programs.  All versions of the extremely popular AppleWorks, and the last Apple II versions of AppleWorks required 128kB of memory.  In the later years of the Apple IIe, the Extended 80-column card was standard on all new machines; and likewise, all Apple II series computers released after the Apple IIe had at least 128 kB of RAM and hardware that acted identically to an Extended 80-column card.

See also
 The M&R Enterprises Sup'R'Terminal — the first 80-Column Text Card for the Apple II
 Videx — manufacturer of the VideoTERM, an 80-Column Text Card for the Apple II

References 

80-Column Text Card
Memory expansion
Graphics cards