Hi @MuriloArima -
Do you have a specific need to create a land cover map from satellite data, and not use existing land cover data? If you do, then you will need to learn a fair amount of GIS to do so, and even more to create a good result.
If not, I agree with @linglingliu87 that it is easiest to use an existing land cover product, and that is usually what people do with InVEST. There are several global datasets to check out. Along with the USGS layer that Lingling pointed to, the European Space Agency provides some, and there are a series from MODIS - these are listed in the Appendix for different models in the InVEST User Guide.
However, it is best if you look for a land cover map that is more accurate for your area than global layers will be. Often, there is at least a national land cover map that can be used, and I recommend first looking for that, before using a global dataset.