The voltage for the electricity in Colombia is 110-120 Volts which is similar to the US and Canada standard. The primary socket shape is the North American grounded and non-grounded sockets.
If the electrical device is not from North America an adapter (for the shape of the plug) may be required. Likewise you should check if your device also needs a transformer (for the voltage).
Adapters and transformers are not so common in Medellin however you should find them at Homecentre (near Poblado Metro Station) and perhaps Exito. Where possible we recommend you buy them before arriving.