Yes you can make them by adding the minus sign/character, so basically:

" - "

On many keyboards the minus key is in the top row of numbers, just to the right of zero.

But the trick is... you have to put a bunch of them (not just one of them)!

I usually I hold down on the minus key a little bit, and a few of them. I also made a special hot key on my keyboard that I can press, that just automatically inserts about 16 of them. (But I don't think it takes that many to generate the line effect.)

These kind of line dividers are highly useful for Redditors like me!

People who have a very annoying habit of typing excessively long comments (such as I am doing here yet again!).

So basically if you suffer from hypergraphia...

And have really fast typing speeds...

Then those sectional line breaks really help separate excessively long comments into nice visual readable chunks/sections, for the poor readers who encounter my comments!

Interestingly this technique is also done in novels, in which chapters can be organized sub sections, to make a chapter yet even more readable.

They sometimes use lines to do that.

Or some authors/publishers sometimes use about 3 asterisks, spaced widely apart, and centered. " * * *" (I can't create that asterisk effect here on Reddit, so I use the line breaks instead.)