This article proposes a dual-tuned, multifunction device using graphene and vanadium dioxide (VO2)-based metasurface for terahertz applications. It provides the capability of voltage tuning and temperature tuning to switch dynamically among the functionalities. The fundamental building block of the metasurface is designed using a lossy silicon dioxide (SiO2) substrate with a reflective gold-based ground layer at the bottom and an elliptical-shaped metasurface layer at the top. The metasurface layer is made of a combination of vanadium dioxide and graphene. At normal room temperature (298 K), the device can be employed as a triple-band absorber with sharp absorption points at 1.98 THz, 2.48 THz, and 3.11 THz with absorption of 96.37%, 99.63%, and 81.23%, respectively. At a higher temperature of 68 °C (341 K) or more, it can be employed as a linear-to-linear cross polarization converter (LTLPC) from frequency 1.62 THz to 2.96 THz, i.e., 58.52% fractional bandwidth (FBW) considering 90% polarization conversion ratio (PCR) level as well as a dual-band absorber with sharp absorption points at 1.69 THz and 3.05 THz with 90.89% and 98.54% absorption, respectively. The operating frequency of the device can also be tuned over the terahertz gap because of the voltage-tuning property of graphene. The response of the device remains outstanding up to the 50-degree opacity angle.