Metamaterials have revolutionized wave manipulation, with absorbers becoming essential for applications in sensing, imaging, and communication. A critical challenge remains designing broadband absorbers with adaptive functionality across the terahertz spectrum. Here, we report on the design and simulation of a straightforward, versatile wideband metamaterial absorber utilizing vanadium dioxide ($\text{VO}_{2}$), capable of functioning in both its metallic and dielectric phases. The proposed unit cell is composed of three main elements: a gold layer that acts as a substrate to prevent light transmission and improve energy absorption, a $\text{SiO}_{2}$ dielectric layer, and a periodic arrangement of $\text{VO}_{2}$-based metamaterial structures placed on top. The $\text{VO}_{2}$ undergoes a phase transition from metallic to dielectric states in response to temperature variations, enabling the structure to alternate between functioning as a full absorber and a full reflector. In the metallic phase, when light is incident normally, the structure functions as a wideband absorber, achieving an absorption efficiency exceeding 0.9 over a frequency range from 1.27 THz to 2.64 THz, with a bandwidth of 1.37 THz. In contrast, in the dielectric phase, the structure becomes an ideal reflector, with absorption efficiency dropping below 0.055 across the 0.1 THz to 4 THz range. The influence of geometric parameters on absorber performance and the impact of varying incident light angles for both TM and TE polarization states are explored. The design's simplicity, combined with its dual functionality as both a perfect absorber and reflector depending on the $\text{VO}_{2}$ phase, and its polarization insensitivity, make it a promising candidate for a range of terahertz applications, including imaging and modulation, which require broad bandwidth capabilities.