Does http/2 run by default?

Is http/2 running by default or do I need to do any setup?

I have ee 3.7.5 and nginx 1.14.0

I went to a testing site and it said http/2 running. All my installation is default though. Do I need any wp plugin?

HTTP/2 is default for EE sites, although you have SSL enabled.

I use cloudflare SSL, does that matter or is it better to switch to letsencypt?

In terms of SSL? It doesn’t matter.

I meant in combination with ee. But I presume it also doesn’t matter.