Some companies allow for online payment or payment through ATMs and self-service kiosks located in communal places such as conjuntos (gated communities), but this requires the money to be withdrawn from a debit card from a bank account in Colombia or a Colombian credit card. Mailing money in any form is unheard of to me in my experience in Colombia; payment in person is the primary method.
For payment of water, gas, and electricity, I pay in cash at banks, Apostar (a national lottery storefront), or Multiservicios (public utility administration office). For phone/internet/cable, I pay in cash at banks. For health insurance, I pay for EPS (basic public health insurance) in cash directly at the service provider office. For Medicina Prepagada, I pay with a foreign credit card at the service provider office or associated bank (in this case, Coomeva).
These apply to the city of Pereira; there are likely similar or other options in other cities. In all cases, the authorized payment centers are listed on each bill.
Paying bills has gotten a lot easier for utilities (EPM), internet, etc. with online facilities if you have a bank account. Go to the supplier's online site and look for "Pay Online" (Pagar En Línea). It usually transfers you to a payment service. You enter your bank username and password number(s) (you must have a primary and secondary set up). The actual bill will come up, you select the payment source (ahorros or something) and you authorize payment. That simple.
Some sites allow you to schedule the payment at the future date when it is due and to authorize future periodic payments.
Also, your bank online services may include "pay online" options for various services.
Used to be you had to go to various authorized electronic pay-points and endure a lot of rigmarole entering contract data, supplier and transaction type; or to go directly to the supplier offices. This last is no fun when you must queue up at the pay office just to make a payment!