My feet have calluses on inner side of them, is there a way to correct my posture to evenly put pressure on the balls of my feet?

Custom orthotics. If you have an abnormal stance or gait causing the calluses then treatment options include custom made orthotics.
Foot calluses. A podiatrist can evaluate your posture & footstep pattern & prescribe orthotics to correct any postural defects. Orthotics may be expensive in the short run but will save your joints & feet in the long run. If professional ones are too expensive, might try dr. Scholl's orthotics found in some department stores. Be sure to buy & wear comfortable, supportive footwear, not flipflops.