How can I paste in NeoVim from an outside source?

Like, if I find a text from Wikipedia, for example, and want to copy and paste it to NeoVim, how can I do it?

Solution

A few ways to do it:

paste as usual while in insert mode (ctrl-v/cmd-v)
paste from the selection registers: + or * (:help registers)
- to paste from a register in insert mode, hit ctrl-r then +
- to paste from a register in normal mode, hit ctrl-"then + then p

Additionally, you can substitute + with any other register to paste from that register. See what's currently stored by running :registers