It's too soon to tell for sure...

This is an unprecedented situation where a head of state's typo became a widely mocked online meme. Essentially, Trump coined a new word and then openly challenged the public to guess what it meant in a follow-up tweet.

A word like this, that becomes famous in a single day, could disappear and remain meaningless, or it could take on a new meaning through viral uses and memes.

As has been established in the other answers, it was almost certainly intended to be the word "coverage," but its ultimate meaning could be completely different depending on whether it sticks around or fades away, and on how slang trend-makers move the meaning. (This is a process that we're participating in right now, along with a lot of the Internet.)

One possibility is that people could use the word as a tongue-in-cheek synonym for bullshit or nonsense, somewhat like the word "balderdash" functions now.

Did you hear what Steve said? That was absolute covfefe.

It's also possible that this was what Trump intended (maybe with the help of some wittier aides) to imply in his follow-up tweet.