The apparent presidential candidate is much better at filing paperwork with the trademark office than he is with the Federal Election Commission ... because he filed docs last month to slap the 'West Day' slogan on clothing and shoes.

Ye, however, has yet to officially register to run for Prez despite his announcement over the weekend.

As for "West Day Ever" ... Kanye filed trademark docs on June 26 covering more than 100 different types of apparel -- t-shirts, hoodies, tracksuits, bomber jackets, turtlenecks, jumpsuits, g-strings, beanies, blazers, infantwear, footwear and everything in between.

The date is significant because it was the same day news broke that the rapper landed a 10-year deal with Gap to launch a new clothing line called Yeezy Gap.

That was when Kanye first tweeted the slogan, saying ... "YEEZY AND GAP FORM PARTNERSHIP #WESTDAYEVER."

He's since used the hashtag to promote the release of a shoe and new music, as well -- and it will likely be a big part of his 2020 campaign ... whenever that starts.

Of course, Kanye needs to do a lot more than just distribute some hats and shirts. He still needs to register with the FEC, present a campaign platform and collect enough signatures -- not just Elon Musk's -- to get on the November ballot.