I interned for Bill Clinton one summer and a crazy woman would send letters every day with a drawing of his head on a different animal's body captioned "William Parrot Clinton" or "William Dolphin Clinton" or "William Giraffe Clinton." And honestly, I think former president Clinton saw at least some of those drawings.
I bring that up because I don't post a lot about politics. I don't think I've ever seen anyone change their mind on social media (also I'm pretty sure Facebook filters it so you only see posts from people who have the same political views as you). But I've interned and volunteered for elected officials and I know that they make decisions based on what constituents seem to care about. Sending a letter/email/calling actually matters. Even if they don't read your specific letter, the offices I worked in would give the bosses a summary of the correspondence coming in and everyone realized they needed to address that if they wanted to keep their jobs. And if you send enough letters, even if they are insane scribbles over drawings of animorphs, you will get heard by the people in power.
It's sad to think that we need to remind our representatives that we don't want people dying in mass shootings or that we don't want innocent civilians to be abandoned in a war or that we want justice when police officers shoot black men and then cover up the evidence. But legitimately, we need to remind them of that.
It takes two seconds to look up contact info for your elected officials on this nonprofit, nonpartisan website: https://www.opencongress.org/people/zipcodelookup