Larry,
The converters converts 110 volts AC shore power into 12 volts DC power to essentially charge your coach battery. At the same time it charges the battery, it has enough power to power the DC items in your RV, such as furnace fan, control circuit for refer, water pump, most lighting, vent fans, electric jacks, any electric slide rooms etc.
An inverter inverts 12 volt (usually) DC power from a battery or bank of batteries into 110 volts AC power so that you can power AC powered items in your coach, to the capacity of the inverter and batteries. AC powered items in your coach such as TVs, stereo system, C-PAP, BI-PAP, refrigerator, air conditioner, microwave etc. That said, it is not usually practical to use inverter power for high-power-demand items like the air conditioner, microwave, space heaters etc. Their current demand will suck the battery bank dry pretty fast.
All coaches come with a converter. Some coaches (from other manufacturers) may be orderable with an inverter. Most RV style inverters have a DC charging circuit in them that in most cases, can eliminate the need to use the OEM supplied converter for battery charging.
That all said, I do not have an inverter and am speaking from what I have read, not what I have experienced. I invite the real experts to please put a finer point on my input.
Jim