Well, unfortunately we Facebook users simply can’t block invitations to "like" pages yet (as of June, 2020)
However, here’s what you can do: on a desktop browser, visit this page: https://www.facebook.com/pages/?category=invites. It aggregates all of your page invites in a single place, and you can dismiss them one by one (click on the
× that appears on hover).
There’s one major omission in the [list of blocking options]: stopping page invites on Facebook. Anyone who likes a page can invite their friends to like it as well, and Facebook even encourages you to do this sometimes. You’ve almost certainly been swarmed with page invites on Facebook at some point.
Unfortunately, there’s currently no way to turn off page invites on Facebook. Based on our testing, locking event invites doesn’t stop page invites.
Make Use Of (dated 06 May, 2020)
(…) All of a sudden, out of the blue, I am getting dozens and dozens of invites to “like” someone’s Facebook page.
At first, I thought it was a side effect of having a pool of Facebook friends approaching the magic 5,000 number. (…)
Upon further informal research, I don’t believe this is the case. I asked a small group of people in the office, and they have ALL seen a tremendous increase in page invites on their Facebook account.
A blog post (dated 06 December, 2019)
Update (as of December, 2020): On the new Facebook design/layout, that page still works on desktop browsers. Now there’s a wide blue
[to follow] or
[to like] option – click on the gray button
⋯ next to it, and then select
⊗ Decline. (Please note it’s also available as the last option in the left sidebar, as