Inverters come in several "Flavors" for practical discussion
Most RV's as factory shipped: NON EXISTENT.. that is you don't have one.
I added one to mine (The 2nd flavor: After market) 2,000 watts More on that later
Factory installed, Small, medium, large And more on that
Small inverters generally 300-600 watts, Run the RV and related electronics, that's all folks (That was the factory option on my Rig)
Medium may add some outlets (say 1,000 watts)
2,000 (Well any over about 1500) adds the microwave
And really big (3,000 or more) May even run an A/C if you have enough battery (you don't trust me there you don't) and a big enough engine charge system (Alternator, and again you don't).
Mine is 2,000 watts, runs TV et-al, GFCI outlets, Optionally oher outlets, (Manual switch) and Microwave.. NOTE: when running ALL outlets I have to be careful not to overload.
And the last pair of pair of flavors
Inverter/converters or Inverter/Chargers These are the "Electronics" part of a UPS in some cases (or at least an IPS) mine switches from LINE to Inverter fast enough that the TV does not even blink...
And "Stand Alone" it only Inverts, That's 12 volt to 120 volt (Mine is configured that way, even if it can charge, I use a different converter)
Most RV's including mine, come from the factory with just a CONVERTER (makes 12 out of 120) Mine came with a darn good one.
THe final choice.. MSW or TSW (Psw) Choose the latter, avoid MSW.