Seconding this: the protocol-ish things to learn about would be microformats2 and webmentions, and then Bridgy can POSSE from anything that supports those (someone probably has a premade WP install by now, lots of folks use static sites but they take more tweaking)
Anyway:
- for a full service see, for example, https://withknown.com/
- for WordPress plugins: https://indieweb.org/WordPress/Plugins#POSSE_Plugins
- one can also use services like IFTTT, Zapier, Integromat, etc to do this, see https://indieweb.org/2020/West/webmentions-and-automation for more
- there's https://brid.gy/about#publishing
... aand a lot more.