Musescore is free but not 100% free of bugs especially the earlier versions. As a long time Musescore user myself, think the latest release is v4.x.
As with many notation programs, you pre-select the note type (quarter, half, whole, etc.) After that use the pointer to place the note on the staff. If you have an electronic keyboard with a USB-MIDI cable to the computer, entering notes would be quicker.
Definitely can do a lot with the program including create an orchestral score with many instruments. Some instruments are not in the standard pitch like horn in F or Bb clarinet. A piano score you can stack up to 4 melodic lines (voices).
Can’t say which is the easiest to learn. The easier ones may not have all the features you need. It’s best to go to YouTube and do a search on notation programs including Forte, Sibelius & Musescore to see which is the easiest for you and best suit your needs.