Replace Mode

Replace mode is similar to insert mode, except typing characters replaces any existing characters, rather than inserting them. When typing reaches the end of a line, replace mode simply inserts the new characters.

Let's take a look at how this works. Starting from the following buffer:

we start by hitting R to enter replace mode.

Now that we are in replace mode, we can simply type new keys to replace the existing content. Note that as we continue typing past the existing text, new text is inserted into the buffer.

Now that we are done replacing text, let's hit Esc to return to normal mode.

That's about it. You can find more details about replace mode in the Neovim docs