A method is presented for producing high-quality, wafer-scale graphene films (up to 3-inch size) on Ni and Cu substrates under ambient pressure, followed by rapid etching of the metal layers and transfer onto arbitrary substrates. The method enables the fabrication of large-area graphene devices, including field-effect transistors (FETs) and stretchable strain sensors. The FETs exhibit hole and electron mobilities of 1,100 ± 70 cm²/Vs and 550 ± 50 cm²/Vs, respectively, at a drain bias of -0.75V. The strain sensors show a piezo-resistance gauge factor of ~6.1, which is significantly better than conventional metal-based strain gauges. The method involves growing graphene on metal substrates, transferring it onto polymer supports, and then removing the metal layers with a solution. The graphene is then transferred to arbitrary substrates, such as PET or PDMS, and patterned using conventional lithography. The large-area graphene films are also used for flexible and stretchable electronics. The method offers improved scalability and processibility for wafer-scale devices and flexible electronics. The graphene films are transparent and conductive, making them suitable for optoelectronic applications such as solar cells and touch sensors. The method allows for the fabrication of wafer-scale device arrays through conventional photolithography processes. The results demonstrate the potential of wafer-scale graphene synthesis and transfer for practical applications in flexible and stretchable electronics.A method is presented for producing high-quality, wafer-scale graphene films (up to 3-inch size) on Ni and Cu substrates under ambient pressure, followed by rapid etching of the metal layers and transfer onto arbitrary substrates. The method enables the fabrication of large-area graphene devices, including field-effect transistors (FETs) and stretchable strain sensors. The FETs exhibit hole and electron mobilities of 1,100 ± 70 cm²/Vs and 550 ± 50 cm²/Vs, respectively, at a drain bias of -0.75V. The strain sensors show a piezo-resistance gauge factor of ~6.1, which is significantly better than conventional metal-based strain gauges. The method involves growing graphene on metal substrates, transferring it onto polymer supports, and then removing the metal layers with a solution. The graphene is then transferred to arbitrary substrates, such as PET or PDMS, and patterned using conventional lithography. The large-area graphene films are also used for flexible and stretchable electronics. The method offers improved scalability and processibility for wafer-scale devices and flexible electronics. The graphene films are transparent and conductive, making them suitable for optoelectronic applications such as solar cells and touch sensors. The method allows for the fabrication of wafer-scale device arrays through conventional photolithography processes. The results demonstrate the potential of wafer-scale graphene synthesis and transfer for practical applications in flexible and stretchable electronics.