how to change to prepaid electricity

{"title":"Limit Load Control Single Phase Watt Hour Meter IP54 Prepaid Electricity Meters","imgUrl":"https:\/\/img.silkroadsl.com\/nimg\/20\/d1\/696c3da3a841eaf89029ff26010b-200x200-1.jpg","attrs":{"Price":"Negotiation","Brand Name":"Calin","Model Number":"CA168-G","Minimum Order Quantity":"Negotiation","Delivery Time":"30 days","Certification":"CE\/SABS\/IEC","Place of Origin":"China","Payment Terms":"western Union,Paypal, T\/T, L\/C","Supply Ability":"70,000pcs per month","Packaging Details":"Carton","Product Name":"GSM 1 Phase STS Prepayment Electric Meter","Network":"GSM EDGE EVDO GPRS","Dimensions":"160x112x58mm","Mounting":"British Standard(BS) 5685","Display":"Backlit LCD 6 digits","Accuracy":"Class 1s","Payment mode":"Prepayment post-payment","Material":"Polycarbonate"}}

{"title":"Contactless RF Intelligent Electric Meter , Prepaid Energy Meter Using Smart Card","imgUrl":"https:\/\/img.silkroadsl.com\/nimg\/6f\/83\/7bd582088b8f73be82bc24522b6b-200x200-1.jpg","attrs":{"Price":"Negotiate","Brand Name":"Radarking","Model Number":"DTSY150\/RF","Minimum Order Quantity":"100pcs","Delivery Time":"30 days","Certification":"IS09001; IS014001; IEC62052-11; IEC62053-21;","Place of Origin":"Made in China","Payment Terms":"Western Union, T\/T, L\/C","Packaging Details":"Standard Package","Supply Ability":"5000000 pcs\/year","Theory":"Three Phase Prepaid Electric Meter","Card Type":"RF Card","Indicator":"LED","Data Storage Period":"More than 10 Years","Refer. Voltage":"3*220V\/230V\/240V","Refer. Current":"3*5(40)A"}}