A modular frame (100, 100A), comprising: a push-button area (110, 110a) comprising: a function key hole group (111, 111a) disposed at a top end of the push-button area (110, 110a); an alphabet key hole group (112, 112a) disposed at a middle of the push-button area (110, 110a); a number key hole group (113, 113a) disposed between the function key hole group (111, 111a) and the alphabet key hole group (112, 112a); a shift key hole (114, 114a) located at one side of the alphabet key hole group (112, 112a), wherein the shift key hole (114, 114a) comprises a first processing region; a space key hole (115, 115a) disposed at a bottom end of the push-button area (110, 110a) opposite to the function key hole group (111, 111a), wherein the space key hole (115, 115a) comprises a second processing region, a third processing region, and a fourth processing region; a backspace key hole (116, 116a) located between the function key hole group (111, 111a) and the alphabet key hole group (112, 112a) and at one side of the number key hole group (113, 113a), wherein the backspace key hole (116, 116a) comprises a fifth processing region; and an enter key hole (117, 117a) located in the alphabet key hole group (112, 112a) and below the backspace key hole (116, 116a), wherein the enter key hole (117, 117a) comprises a sixth processing region and a seventh processing region, the modular frame (100, 100A) being characterized in further comprising: a plurality of rib structures (120, 120a) selectively disposed in at least one of the first processing region to the seventh processing region to switch the modular frame (100, 100A) to a first configuration, a second configuration, or a third configuration, wherein each of the rib structures (120, 120a) comprises two engaging portions and two through holes, and each of the first processing region to the seventh processing region comprises two positioning grooves and two hot melt pillars, the two engaging portions of each of the rib structures (120, 120a) are adapted to be disposed in the corresponding two positioning grooves, the two hot melt pillars are adapted to be disposed through the corresponding two through holes, and each of the hot melt pillars is adapted to melt when heated, to adhere each of the rib structures to the push-button area. a function key hole group (111, 111a) disposed at a top end of the push-button area (110, 110a); an alphabet key hole group (112, 112a) disposed at a middle of the push-button area (110, 110a); a number key hole group (113, 113a) disposed between the function key hole group (111, 111a) and the alphabet key hole group (112, 112a); a shift key hole (114, 114a) located at one side of the alphabet key hole group (112, 112a), wherein the shift key hole (114, 114a) comprises a first processing region; a space key hole (115, 115a) disposed at a bottom end of the push-button area (110, 110a) opposite to the function key hole group (111, 111a), wherein the space key hole (115, 115a) comprises a second processing region, a third processing region, and a fourth processing region; a backspace key hole (116, 116a) located between the function key hole group (111, 111a) and the alphabet key hole group (112, 112a) and at one side of the number key hole group (113, 113a), wherein the backspace key hole (116, 116a) comprises a fifth processing region; and an enter key hole (117, 117a) located in the alphabet key hole group (112, 112a) and below the backspace key hole (116, 116a), wherein the enter key hole (117, 117a) comprises a sixth processing region and a seventh processing region, the modular frame (100, 100A) being characterized in further comprising: a plurality of rib structures (120, 120a) selectively disposed in at least one of the first processing region to the seventh processing region to switch the modular frame (100, 100A) to a first configuration, a second configuration, or a third configuration, wherein each of the rib structures (120, 120a) comprises two engaging portions and two through holes, and each of the first processing region to the seventh processing region comprises two positioning grooves and two hot melt pillars, the two engaging portions of each of the rib structures (120, 120a) are adapted to be disposed in the corresponding two positioning grooves, the two hot melt pillars are adapted to be disposed through the corresponding two through holes, and each of the hot melt pillars is adapted to melt when heated, to adhere each of the rib structures to the push-button area. a plurality of rib structures (120, 120a) selectively disposed in at least one of the first processing region to the seventh processing region to switch the modular frame (100, 100A) to a first configuration, a second configuration, or a third configuration, wherein each of the rib structures (120, 120a) comprises two engaging portions and two through holes, and each of the first processing region to the seventh processing region comprises two positioning grooves and two hot melt pillars, the two engaging portions of each of the rib structures (120, 120a) are adapted to be disposed in the corresponding two positioning grooves, the two hot melt pillars are adapted to be disposed through the corresponding two through holes, and each of the hot melt pillars is adapted to melt when heated, to adhere each of the rib structures to the push-button area.